Instruments and techniques for orienting prosthesis components for joint prostheses

ABSTRACT

The present invention is directed to a modular assembly for an arthroplasty in a long bone and methods for achieving an anatomically accurate reconstruction. A modular arthroplasty assembly includes the components of: a convertible offset coupler bounded on a first side by an implant surface adapted to receive an implant component, and bounded on an opposite second side by a bone anchor engagement surface, prosthesis component and a bone anchor configured to be inserted in bone and adapted for engagement with the convertible offset coupler. Together, the components of the system, including the array of selectable engagement orientations of the components, enables adaptation to the existing anatomy of the patient and the ability to most closely achieve the native anatomy of the healthy shoulder joint so as to provide the patient with the most natural use of the joint. The system also provides a solution for reverse arthroplasty and conversion from anatomically correct to reverse that avoids a boney procedure on revision and minimizes humeral distalization.

RELATED APPLICATIONS

This application claims the benefit of the filing date of U.S.Provisional Patent Applications No. 61/921,593 filed Dec. 30, 2013, andNo. 61/928,399 filed Jan. 16, 2014.

FIELD

The disclosure relates to the field of joint replacement, and moreparticularly total shoulder arthroplasty using prosthetic components toachieve anatomical and reverse, and revision arthroplasty.

BACKGROUND

Anatomic and Non-Anatomic Shoulder Replacement

In the field of shoulder arthroplasty, there are two general andsomewhat competing points of view regarding the state of the patient'sanatomy. From the point of view of some clinicians, it is desirable toaim for restoration of the native anatomy through use of prostheticshoulder components that are shaped in a manner that is anatomicallycorrect, particularly with regards to the shape of the prosthetichumeral head. For others, the higher objective is to aim for adaptingand balancing the existing soft tissues, particularly the rotator cuffand musculature, with the shape and orientation of the replacementhumeral head, even if the shape of the prosthetic head is notanatomically correct.

Shoulder arthroplasty typically requires removal of the entire head ofthe humerus bone, commonly at or below the anatomical neck, toaccommodate insertion of a prosthesis, typically in the form of ahead-bearing elongated shaft (referred to herein as a stem), into thediaphysis of the humerus, and in alternate approaches a stemless systemincludes a cage or other support structure that is not elongate. Thehead portion of the prosthesis provides an articulation surface thatcooperates with an opposing articulation surface, the glenoid, which ison the boney portion of the scapula. In some instances, the head andstem of the prosthesis are unitary, while in other instances, the headand stem are provided as discrete components that are engageable by avariety of means, such as a male taper and female receiver. Within theart, there is a wide array of choices with respect to stem features, interms of length, width, taper, and dimensions, as well as shape andtexture. Likewise, there is a wide array of choices with respect tohumeral head shape, dimensions, pitch, and the like.

Stemless shoulder prostheses are also known in the art. Such prosthesesare offered currently in Europe commercially, and are underinvestigation in the United States. The stemless systems are consideredanatomically accurate by nature due to the generally greater ease ofcomponent positioning as compared with systems that use stems. Thestemless systems utilize spherical humeral heads in all variations. Thestemless systems are particularly desirable because they involve lessinvasive boney operations, and because the surgical technique itself isnot as technically demanding, since the final position of the prosthetichead is not constrained by the long axis of the bone due to the shortlength of the prosthesis. Fixation is offered in a variety of keeled,caged, caged-pegged configurations. However, poor bone quality presentsconcern for long-term durability of stemless arthroplasty, and poor bonequality is considered a contraindication for use of a stemlessprosthesis. This limits the utility of stemless implants typically topatients who are young, since elderly patients—who are most often inneed of joint replacement—often have osteopenic bone, and are thusexcluded from the possibility of stemless shoulder arthroplasty.

The anatomic approach involves restoration of the humeral head to itspre-diseased state, with utilization of spherical humeral headcomponents with proportional diameter and thickness. In contrast, thenon-anatomic approach involves humeral head replacement with soft-tissuebalancing of the rotator cuff utilizing spherical humeral headcomponents of varying thicknesses. Generally within the art, reverseshoulder arthroplasty is considered non-anatomic shoulder replacementbecause the native glenoid side of the shoulder is converted to a sphereto mimic the humerus (glenosphere), while the humeral side is convertedto mimic a glenoid (typically through replacement of the humeral headwith a cup shaped implant).

Desired features of anatomic implants include replication of humeralneck angle, version, and posterior and medial offset. In the currentart, stemmed arthroplasty systems are the most prevalent, andessentially all stemmed arthroplasty systems use spherical humeralheads. The conventional belief is that roughly one-third of a sphere isconsidered to be the most anatomically correct shape of the currentofferings. Regardless of head size, the ratio of the head height to theradius of curvature is about 3:4. Clinical outcomes in patients who havereceived anatomically correct prostheses are generally regarded assuperior when compared to soft-tissue balancing techniques usingnon-anatomically shaped (i.e., anatomically incorrect) prostheses.

Whether or not an implant is anatomically correct, some implants in theart are designed to be usable in either a standard to a reverseconfiguration. Typically within the art, convertible implants allow thesurgeon to convert by removing the standard prosthetic head from thestem, and replacing the head with a cup (to mimic the glenoid) (exampleswithin the art include convertible shoulder arthroplasty systems byBiomet, Zimmer, Tornier, Exactech). With such prostheses, the cup sitson top of the bone cut rather than being recessed within the bone. Adisadvantage of this technique and prosthesis design is that the humerusbecomes overlengthened or distalized, predisposing the patient to nervestretch injury, joint stiffness, and acromial fracture. Thus, whilethese convertible systems offer the benefit of a less invasivereoperation, the trade off is increased risk of surgical complicationsand inferior biomechanical outcomes, all of which are due to theincreased height of the implant that result from placement of the cupabove the bone cut. This is particularly true with respect to reverseshoulder revisions when compared to primary reverse shoulderarthroplasty that is achieved with a reverse-specific implant where thecup is recessed into the proximal humerus bone (examples within the artof primary reverse shoulder arthroplasty systems include those by DJOSurgical, DePuy, and Tornier). Arm lengthening, nerve palsies, jointinstability, impingement, joint stiffness, acromial fractures, anddifficulty with prosthesis conversion that ultimately leads to stemextraction and bone fracture are all examples of undesirable clinicaloutcomes resulting from current convertible and primary arthroplastysystems.

Most reverse shoulder arthroplasty systems are designed to deliberatelyshift the rotational center of the joint in order to take what isbelieved to be best advantage of the remaining musculature by tensioningthe deltoid to compensate for loss of rotator cuff function. Theapproach yields a distal shift of the arm/humerus (i.e., towards thedirection of the patient's feet). This distal shift is achieved throughan increase in the overall length of the humerus through the height ofthe implant beyond the cut line of the humeral head. While there areperceived advantages to this approach, known problems that come withincreased distalization of the arm include 1) acromial scapularfracture, and 2) nerve injury from the stretch on the nerves. Indeed,while some experts may tout the advantages of increasing deltoidtension, others report that” . . . an increase in passive tension of thedeltoid on the acromion, can lead to fatigue, stress, or completefracture [Hamid N, et al. Acromial Fracture After Reverse ShoulderArthroplasty. Am J Orthop. 2011.40(7):E125-E129]. Werner et al reporteda 7.3 incidence of scapular fracture in revision cases, and a 6.3%incidence during primary arthroplasty [Werner C M, et al. Treatment ofpainful pseudo-paresis due to irreparable rotator cuff dysfunction withthe Delta III reverse-ball-and-socket total shoulder prosthesis. J BoneJoint Surg Am. 2005.87:1476-86]. Others have reported a 7.7% incidenceof neuropraxia during revision reverse shoulder arthroplasty [TotalReverse Shoulder Arthroplasty: European Lessons and Future Trends.Seebauer L. Am J Orthop. 2007.36(12 Supplement):22-28.]. The highincidence of nerve injury is probably due to the stretch on the brachialplexus nerves that occurs as the humerus is lengthened. Especially inpatients with stiff, contracted shoulders, it is not advisable toover-lengthen the arm. In view of these undesirable clinical effectsthat derive from the mechanical lengthening of the bone, there is a needto provide an arthroplasty system that is specifically designed to avoiddistalization.

Yet another challenge in the art is the absence of anatomically correcthead articulation surfaces. It is know that the native anatomical shapeof the humeral head is not spherical, but elliptical (i.e., where thecross section of the humeral head has a radius of curvature in thesuperior to inferior dimension that is greater than the radius ofcurvature of the cross section in the anterior to posterior dimension).Recent research has shown that a prosthetic humeral head having a crosssectional shape adjacent to the bone cut that is elliptically-shaped anda generally spherical center point would theoretically allow a patientto have improved shoulder range of motion and function postoperatively.However, because the center of rotation of the humeral head is offsetfrom the long axis of the humeral bone, it has been impractical for anyshoulder implant company to create a prosthesis with anelliptically-shaped prosthetic humeral head. Merely coupling anelliptically-shaped head with a traditional stemmed prosthesis designwould present difficulties accounting for the surgeon's need tosimultaneously achieve the proper head size, correct rotationalorientation of the elliptical head, and the proper amount of superior toinferior and anterior to posterior offset relative to the stem.

Moreover, in many shoulder surgeries, only the humeral portion of thejoint is replaced while the native glenoid is left intact, presenting achallenge of matching the articulating surface of the head prostheticwith the native articulating surface of the glenoid. This challenge isnot present in total arthroplasty, where both the humeral and theglenoid portions are replaced with prosthetics. Ideally, a shoulderarthroplasty system would provide a wide range of head choices andoffsets to most precisely match the patient's native anatomy. With sucha system, a near perfect match could be achieved in a hemi-arthroplasty,and in if the system were modular, could be adapted in a revision toprovide an ideal match if the shoulder is converted to either a totalarthroplasty or to a reverse shoulder arthroplasty. The current art doesnot provide such modular systems, thus, to accomplish the desirableoffsets with traditional stem designs, whether using spherical orelliptical heads, it would be necessary to stock an essentially infiniteinventory of prosthetic heads and/or stems with variable offsets forachieving the desired shape, size and positioning, which is, of course,economically impractical.

Another challenge in joint replacement is the general requirement forcomplete implant removal in the instance where a corrective or revisionsurgery is needed with a primary arthroplasty system. A common featureamong the shoulder arthroplasty devices in the art is that they aretypically designed for a single use, and typically cannot be repurposedin a later surgery on the same patient. That is to say that any postimplantation procedure which the patient may require due to further boneor soft tissue deterioration, such as a revision or conversion to areverse configuration, typically requires a bony procedure wherein allor a portion of the implanted prosthesis must be removed from bone inorder to allow implantation of a new device. It is well known that in apercentage of initial shoulder arthroplasty cases, the patient willrequire revision surgery due to device failure, infection, or furtherdegeneration of the bone or soft tissues of the joint. In some specificsituations, the revision will require conversion of the humeral side ofthe joint from a standard implant to a reverse implant. It is desirable,though typically not possible, to avoid any bony procedure duringrevision cases because there is a high risk of humeral fracture and/orbony destruction when the surgeon attempts to remove a well-fixedhumeral component from the humerus. It is desirable to advance the artwith devices that achieve structural stability of an implant within thebone while retaining the ability to remove the device without bonefracture or catastrophic loss of bone during removal.

The objective of implant stability is addressed, in the context of longbones, through implant length, proximal diameter, and material selectionand surface treatment that can enhance bony ingrowth on the implant. Inthe art of shoulder arthroplasty, there are a variety of short-stemmedand stemless devices that have implant surface features that encouragebony ingrowth and implant dimensions that are intended to achievestability. While these features are helpful to encourage securementwithin bone, they are developed based on averages within a broad patientpopulation, for example in terms of proximal humerus head and diaphysisdimensions, and contribute to some of the other challenges ofarthroplasty in that they provide only a limited range of possibledevice configurations and features for achieving bony fixation. And itis a well known problem that removal of a prosthesis component that iswell fixed in the bone is made more difficult when the structuralfeatures of implant components limit the surgeon's ability to applysurgical instruments such as an osteotome to free the prosthesis fromthe bone, especially in the metaphyseal and diaphyseal regions. It isthe very structural elements that provide the opportunity for enhancedfixation that also lead to significant bone damage and loss in thelikely event that a revision is needed. The art presently lacksarthroplasty implants with features that enable achievement of bonyfixation and enable removal of components for revision to minimize boneloss while enabling the repurposing of the primary implants foralternate use.

A need exists to provide a humeral prosthesis that is designed to bemodular and adaptable to enable a closer approximation of nativeanatomical fit for a broader range of patients rather than a patientpopulation. Further, there is a need for a device that mitigates theproblems associated with height position of a prosthesis in the humerusbone at the time of the index procedure and/or a revision surgery sothat distalization of the humerus is avoided if conversion to a reverseshoulder arthroplasty is required. And there is a need for devices thatare optimized for proximal bony ingrowth and distal (diaphyseal)stability to achieve short and long term device stability whileretaining the ability to revise and possibly remove the implant withoutcatastrophic bone effects. While some devices and device features existwithin the art that are designed to protect against humeral bone loss inrevision surgeries, there remains a need for a system that enablesreplacement or conversion of a humeral prosthesis without therequirement for bony procedure or at least minimal need for removal ofimplant from within the bone. To address needs in the art, including theseveral needs identified, this disclosure provides a system that ismodular and convertible and optimized achieve closer approximation of apatient's native anatomy, including avoidance of arm distalization,avoidance of surgery-related bone loss, while enabling a wider range ofoptions for matching anatomy on during the index procedure as well asduring surgical revision.

SUMMARY

This disclosure is directed to components, systems, and methods forshoulder arthroplasty. In particular, the disclosure provides solutionsfor achieving anatomically correct hemi and total arthroplasty andreverse arthroplasty, in primary and revision surgery. In particular,the disclosure provides solutions for addressing the challenges facedwhen a standard shoulder arthroplasty requires revision surgery,including revision from standard to reverse shoulder arthroplastywherein the orientation of the humeral head and glenoid are switchedfrom their typical anatomical orientation. And this disclosure providessolutions currently lacking in the art that would enable a surgeon toachieve revision arthroplasty without risk of substantial humeral boneloss or fracture, among other benefits. This disclosure also providessolutions for achieving an optimized anatomical match of an arthroplastysystem to a patient's anatomy. Surgical methods and techniques areprovided for achieving placement of arthroplasty components, and forselecting and optimizing anatomical positioning of components to bestmatch a patient's native anatomy.

According to the instant disclosure, a variety of implant embodimentsare disclosed as well as techniques for selecting implant components toachieve a close replication of the native anatomy of a patient receivingprimary native or reverse orientation shoulder arthroplasty, as well asrevision. Thus, embodiments are provided that create a more anatomicsuite of standard and stemless implants that are more biomechanicallysound both at the time of primary standard total arthroplasty,hemi-arthroplasty and reverse shoulder arthroplasty surgery, as well asduring revision surgery.

As further described herein, some of the benefits of the disclosedimplants and techniques pertain to a “convertible offset coupler” or“coupler” which is alternately referred to herein as a “metaphysealshell” in the context of shoulder arthroplasty systems, and whichfunctions in some aspects to position and retain an implant component,such as, for example, a humeral head or a cupped reverse prosthesis (a“concave cup” or “concave poly cup”) for replicating a glenoid featureon humeral bone. In some exemplary embodiments, this metaphyseal shellis positioned by countersinking in bone, such as the cut humeral headbone in the case of shoulder arthroplasty, in a region that is proximateto or within the metaphysis (wide portion of the long bone between theepiphysis—head—and the diaphysis—the shaft). In other embodiments, thismetaphyseal shell is positioned partially within the bone or on the cutsurface of the bone for cases in which achieving anatomical match in apatient necessitates increased height on the superior aspect of thehumerus.

Advantageous features of the metaphyseal shell that are describedfurther herein include: an eccentric engagement feature or coupler onthe back or inferior (bone facing) side, such as a standard tapercoupler (Morse-taper in some embodiments), that is selected forengagement with a bone stem, plug or cage (selected in size foranatomical match with the metaphyseal/diaphyseal portions of the longbone) to replicate and achieve native or normal humeral posterior andmedial offset. And, on its top or superior (articulation surface facing)side, a seat, such as a recess, that is adapted to accept both humeralhead and humeral cup (reverse prosthesis) components. The metaphysealshell addresses the mechanical challenge of orientation of spherical andmost particularly non-spherical humeral head components using thecoupler to achieve any anatomically desired offset in either or both theinferior/superior axis and anterior/posterior, and selecting forplacement using instrumentation as described herein to achieve optimalanatomical alignment of the prosthetic articulation surface relative tothe humeral bone.

In an exemplary embodiment according to this disclosure, a modulararthroplasty assembly includes the components of: (a) a convertibleoffset coupler bounded on a first side by an implant surface adapted toreceive an implant component, and bounded on an opposite second side bya bone anchor engagement surface (“metaphyseal shell”) (b) an prosthesiscomponent selected from one of a humeral head (“head”) and a cuppedreverse prosthesis (“cup”), and (c) a bone anchor configured to beinserted in bone and adapted for engagement with the convertible offsetcoupler (“stem” or “plug”).

According to the various embodiments, the modular system for long bonearthroplasty provides prosthesis, anchor and coupler components that areengageable to provide an arthroplasty assembly wherein the position ofthe prosthesis component can be varied rotationally around a sharedcentral engagement axis with the coupler component, the position of theanchor component relative to the coupler component can be varied in twodimensions on a plane that is perpendicular to the central engagementaxis of the coupler and prosthesis components by selecting the couplercomponent from an array comprising a plurality of coupler componentsthat include variably positioned anchor engagement features. Inaccordance with the invention, each of at least two of the plurality ofcoupler components comprises at least one anchor engagement feature thatis off-center from a center point of the coupler component, and theoff-center engagement feature on each of the at least two couplercomponents is at a different distance in at least one dimension that isperpendicular to the central engagement axis. In use, when the couplerand anchor components are recessed into bone, the assembly achievesalignment of the bone articulation surface of the prosthesis componentwith the bone that is anatomically similar to a native long bone.

In the various embodiments, the stem and the metaphyseal shell are eachadapted with at least or one another of a male insert and a femalereceiver channel (such as a Morse type taper), and optionally one ormore of a pin or setscrew or other fastener to achieve engagement therebetween. In some embodiments, the metaphyseal shell bears on a lateralperipheral edge a surface feature that is adapted to enhancing boneyingrowth. In various embodiments, the implant surface of the metaphysealshell and the engagement surface of the prosthesis articulating surfacecomponent have reciprocal engagement features for fixing engagementthere between.

In one embodiment of a head, the head and the metaphyseal shell are eachadapted with at least one or another of a male insert and a femalereceiver channel (such as a Morse type taper) for engagement therebetween. In one embodiment of a cup, the cup and the metaphyseal shellare each adapted with at least one or another of snap fit toothengagement features for engagement there between. In some embodiments,the metaphyseal shell includes engagement features that allow engagementand fixation with each of the head and cup prostheses. In otherembodiments, a metaphyseal shell is adapted with one or the other ofhead and cup prosthesis engagement features. Optionally, in someembodiments, the system comprises a modular diaphyseal stabilizerattachable to the distal end of the stem and selected to match the innerdiameter of the diaphysis. Together, the components of the system,including the selectable engagement orientations of the components,enables adaptation to the existing anatomy of the patient and theability to most closely achieve the native anatomy of the healthyshoulder joint so as to provide the patient with the most natural use ofthe shoulder.

In various embodiments, the methods include surgical techniques forpreparation for and implantation of the modular arthroplasty assembly,wherein one or both the humeral stem and the metaphyseal shell arecompletely or partially recessed within the humeral bone. In particularembodiments, the surgical techniques for revision surgery involvingpreviously implanted modular arthroplasty assembly enable modularadjustment, removal and replacement of the prosthesis component withoutsubstantial compromise or removal of humeral bone. In some embodiments,the surgical techniques provided herein enable conversion of a shoulderjoint from native to a reverse configuration.

In various embodiments, the methods include surgical techniques forimplantation of the modular arthroplasty assembly wherein themetaphyseal shell is completely or partially recessed within the humeralbone. According to the various embodiments, placement of one or both thehumeral stem and the metaphyseal shell within the bone (i.e., below thecut line) allow a greater range of options with respect to establishingthe desired center of rotation in the shoulder joint. It is known in theart and deemed desirable by some to distalize the humerus during areverse shoulder arthroplasty procedure, putatively because greaterheight in the humeral implant distalizes the humerus and puts increasedtension on the deltoid muscle to compensate for lost rotator cufffunction. However, there are clinical and mechanical disadvantages tothis distalization. Unfortunately, these disadvantages are not easilyavoided with implant systems in the art, particularly in the case ofcurrent convertible systems, because of the increased height of thehumeral implants from the extension of the stem and other componentsabove the bone cut line of the humerus. The current disclosure, invarious embodiments, provides an modular and convertible arthroplastysystem that is low profile, having a substantial reduction of implantheight as compared with what is know in the art. These embodiments aredesirable for avoidance of distalization, particularly in reversearthroplasty, enabling the surgeon to avoid mechanical and clinicalproblems associated with the rotational center of the joint, andenabling the use of other options for achieving soft tissue function toreplace the rotator cuff.

Further, in accordance with some exemplary embodiments, the countersunkposition of the metaphyseal shell below the bone cut allows the surgeonto achieve a more anatomical configuration than other systems canachieve at time of primary or revision surgery. In particular, theposition and features of the metaphyseal shell enable substitution ofarticulation surface prostheses, and as needed, removal of the shellduring a revision. In some embodiments, removal of the shell enablesreplacement with a shell having an alternate offset to enable maximumflexibility for achieving desired anatomical structure in a revisionsurgery.

To facilitate removal from bone, the metaphyseal shell has a lateraledge that is in some exemplary embodiments roughened or porous coated toachieve bony ingrowth for reliable fixation, while the bottom of themetaphyseal shell is smooth to prevent bony coupling in someembodiments, thus allowing for greater ease of removal from bone shouldthat be necessary in a later procedure. Taking advantage of theconvertibility, and ease of selection of head/cup implant components,the metaphyseal shell allows for minimal bone removal or manipulation attime of revision/conversion. And, as further described herein, the useof the metaphyseal shell trial with marking features enables precise andvirtually unlimited increments of offset adjustability, eliminating needfor large inventory of prosthetic heads and cups. The options foradjustability are particularly wide when the metaphyseal shell is usedin combination with a suite of stems that are size and shape adapted fora wide range of patient anatomy.

Thus, as compared to other systems in the art, the disclosed systemenables achievement of a more anatomically accurate joint replacementaimed at reducing clinically adverse consequences. And the metaphysealshell with its eccentric taper enables a wider range of selection ofhead/cup orientation without compromise of height, neck angle, version,and posterior and medial offset. This offset function, together with theanatomical benefits thereby attained, finally solves a vexing challengein the art. That is, provision for truly adaptable and convertible,anatomically accurate implants—a challenge that has been heretoforeaddressed, inadequately at best, with either expansive prosthetic headinventory and/or adjustable systems that sacrifice one or more of theanatomically desirable implant features such as component height, neckangle, version, and posterior and medial offset.

This disclosure describes various exemplary convertible implantcomponents and systems, convertible shoulder prosthesis systems, andmethods for implantation of these. While the description below setsforth details of features of the modular arthroplasty assembly, one ofskill will appreciate that the features may also be shared by othersystem components, such as those that are used to determine implant sizeand positioning, generally referred to as trials. Moreover, the featuresand elements as described herein for the shoulder and humerus may bereadily adapted for use in the context of other long bones.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the general inventive concepts will becomeapparent from the following description made with reference to theaccompanying drawings, including drawings represented herein in theattached set of figures, of which the following is a brief description:

FIG. 1 shows a side view of an embodiment of a modular arthroplastyassembly with a stem (“anchor component”), assembled in the context ofshoulder bone;

FIG. 2 shows alternate perspective views of an embodiment of a modulararthroplasty assembly with a stem in the context of bone;

FIG. 3 shows an exploded side view of an embodiment of a modulararthroplasty assembly with a stem, showing alternate stem lengths andalternate embodiments of an articulation surface (“prostheticcomponent”) in the form of a spherical head and a concave poly cup;

FIG. 4 shows alternate back, front, perspective and side views of anembodiment of a modular arthroplasty assembly with a stem, showing anarticulation surface in the form of a spherical head, a frustoconicalshaped metaphyseal shell (“coupler component”) and shell-stem lockingpin, and stem;

FIG. 5 shows alternate perspective and top views of an embodiment of ametaphyseal shell;

FIG. 6 shows alternate side and cross-sectional perspective views of anembodiment of a metaphyseal shell;

FIG. 7 shows alternate perspective views of an embodiment of a stemlessarthroplasty assembly with a plug (alternate embodiment of an “anchorcomponent” in the form of a cage) with an articulation surface in theform of a spherical head, assembled in the context of bone;

FIG. 8 shows perspective views of two alternate embodiments of astemless arthroplasty assembly with a plug, each with an articulationsurface in the form of a spherical head;

FIG. 9 shows an exploded perspective view of an embodiment of a modularstemless arthroplasty assembly with a plug with an articulation surfacein the form of a spherical head;

FIG. 10 shows alternate views of an embodiment of a stemlessarthroplasty assembly with a plug and with an articulation surface inthe form of a concave poly cup, assembled in the context of bone andalone;

FIG. 11 shows a side view and a side view in cross section of anembodiment of a metaphyseal shell having a frustohemispherical shape;

FIG. 12 shows a top view and a side view of an embodiment of ametaphyseal shell;

FIG. 13 shows a top view and a side view of an alternate embodiment of ametaphyseal shell;

FIG. 14 shows a side view and a side view in cross section of anembodiment of a metaphyseal shell, and a side view and a side view incross section of an alternate embodiment of a metaphyseal shell;

FIG. 15 shows an array of sizes of a representative embodiment of ametaphyseal shell shown from the side, the top and the bottom;

FIG. 16 shows alternate perspective views of an embodiment of adiaphyseal stem;

FIG. 17 shows a side view of an embodiment of a diaphyseal stem, inlongitudinal cross section, and a front view of an embodiment of adiaphyseal stem, in cross section along a plane that is parallel to theproximal face;

FIG. 18 shows a top view of an embodiment of a diaphyseal stem, and abottom view of an embodiment of a diaphyseal stem;

FIG. 19 shows a front view of an embodiment of a diaphyseal stem, and aback view of an embodiment of a diaphyseal stem;

FIG. 20 shows a side views of an embodiment of a diaphyseal stem indifferent sizes in solid form, and alternate side views of an embodimentof a diaphyseal stem;

FIG. 21 shows a side view of an overlay of an array of sizes of arepresentative embodiment of a diaphyseal stem showing the variation incontour at the proximal end as a function of size;

FIG. 22 shows a side view of an array of sizes of a representativeembodiment of a diaphyseal stem;

FIG. 23 shows alternate side, front and front cross-sectional views of arepresentative embodiment of a diaphyseal stem;

FIG. 24 shows a side view of an selection of sizes of a representativeembodiment of a diaphyseal stem engaged with a metaphyseal shell, in thecontext of bone;

FIG. 25 shows a front view of an selection of sizes of a representativeembodiment of a diaphyseal stem engaged with a metaphyseal shell, in thecontext of bone;

FIG. 26 shows a front cross-sectional view of an selection of sizes of arepresentative embodiment of a diaphyseal stem engaged with ametaphyseal shell, in the context of bone;

FIG. 27 shows alternate side and perspective views of the shellengagement end (proximal end) and a bottom (distal end) view of arepresentative embodiment of a stem;

FIG. 28 shows a view of a selection of assembled representativeembodiments of a metaphyseal shell and diaphyseal stem showingrepresentative offsets to accommodate patient anatomy;

FIG. 29 shows a perspective view of two sizes of standard lengthdiaphyseal stems showing representative relative positions of theengagement receiver (female taper) as the girth of the stem changes;

FIG. 30 shows a perspective view of an embodiment of a prosthesisarticulation surface in the form of a spherical head, and a side view ofan embodiment of a prosthesis articulation surface in the form of aspherical head, in cross section;

FIG. 31 shows a perspective view of an embodiment of a prosthesisarticulation surface in the form of an elliptical head, a side view ofan embodiment of a prosthesis articulation surface in the form of anelliptical head, and a side view in cross section;

FIG. 32 shows a perspective view of an embodiment of a prosthesisarticulation surface in the form of a glenoid, and a perspective view ofan embodiment of a prosthesis articulation surface in the form ofglenosphere;

FIG. 33 shows a top view of an embodiment of a prosthesis articulationsurface in the form of a spherical head, and a bottom view of anembodiment of a prosthesis articulation surface in the form of aspherical head;

FIG. 34 is a top view of a size array of an embodiment of a prosthesisarticulation surface in the form of a spherical head;

FIG. 35 is a perspective view of an embodiment of a prosthesisarticulation surface in the form of a spherical head showing the radiusof curvature in the AP plane;

FIG. 36 shows a top view of an embodiment of a prosthesis articulationsurface in the form of a elliptical head, and a bottom view of anembodiment of a prosthesis articulation surface in the form of aelliptical head;

FIG. 37 is a top view of a size array of an embodiment of a prosthesisarticulation surface in the form of a elliptical head;

FIG. 38 shows a perspective view of an embodiment of a prosthesisarticulation surface in the form of a elliptical head showing the radiusof curvature in the AP and SI planes;

FIG. 39 shows a perspective view of an embodiment of a prosthesisarticulation surface in the form of a concave poly cup;

FIG. 40 is a side view of an embodiment of a prosthesis articulationsurface in the form of a concave poly cup, in cross section;

FIG. 41 is a top view of an embodiment of a prosthesis articulationsurface in the form of a concave poly cup;

FIG. 42 is a bottom view of an embodiment of a prosthesis articulationsurface in the form of a concave poly cup;

FIG. 43 is a side view of an embodiment of a prosthesis articulationsurface in the form of a concave poly lock having a first embodiment ofa metaphyseal shell lock feature;

FIG. 44 is a perspective view of an alternate embodiment of a prosthesisarticulation surface in the form of a concave poly cup;

FIG. 45 is a side view of an alternate embodiment of a prosthesisarticulation surface in the form of a concave poly cup, in crosssection;

FIG. 46 is a top view of an alternate embodiment of a prosthesisarticulation surface in the form of a concave poly cup;

FIG. 47 is a bottom view of an alternate embodiment of a prosthesisarticulation surface in the form of a concave poly cup;

FIG. 48 is a side view of an embodiment of a prosthesis articulationsurface in the form of a concave poly lock having an alternateembodiment of a metaphyseal shell lock feature;

FIG. 49 is a side view of an alternate embodiment of a modulararthroplasty assembly with a short stem and a distal diaphyseal fixationfeature;

FIG. 50 is an perspective view of an alternate embodiment of a modulararthroplasty assembly showing a spherical head and an offset coupler forengagement with one or more of a stem and a metaphyseal shell and ashort stem;

FIG. 51 is an exploded perspective view of an alternate embodiment of amodular arthroplasty assembly with a glenoid, spherical head, offsetcoupler and stem;

FIG. 52 is a graphic depiction of steps of a representative embodimentof a surgical technique for implanting an arthroplasty system inaccordance with the disclosure;

FIG. 53 is a graphic of a step in the sequence of a representativeembodiment of a surgical technique for implanting an arthroplasty systemin accordance with the disclosure showing a side view of a humerus and acut line for excision of a portion of the humeral head, and showing aperspective view of a bone cut on a humerus revealing metaphyseal boneand alignment tool for central placement of a Kirchner wire (“K-wire”);

FIG. 54 is a graphic of a step in the sequence of a representativeembodiment of a surgical technique for implanting an arthroplasty systemin accordance with the disclosure showing a perspective view of a bonecut on a humerus revealing metaphyseal bone and alignment toolpositioned on the bone cut and placement of a K-wire, and showing aperspective view of a bone cut on a humerus revealing reamed metaphysealbone and K-wire;

FIG. 55 is a graphic of a step in the sequence of a representativeembodiment of a surgical technique for implanting an arthroplasty systemin accordance with the disclosure showing a perspective view of a bonecut on a humerus with a stem broach;

FIG. 56 shows a representative embodiment of an offset tool;

FIG. 57 shows an alternate view of the representative embodiment of anoffset tool shown in FIG. 56;

FIG. 58 is a graphic of a step in the sequence of a representativeembodiment of a surgical technique for implanting an arthroplasty systemin accordance with the disclosure showing a perspective view of a bonecut on a humerus with a stem trial in place and representative shelloffset selection tool, and showing a perspective view of a bone cut on ahumerus with a stem trial and representative shell offset selection toolin place indicating selected offset;

FIG. 59 is a graphic of a step in the sequence of a representativeembodiment of a surgical technique for implanting an arthroplasty systemin accordance with the disclosure showing alternate perspective views ofa bone cut on a humerus with a representative shell trial withindicators for offset selection, and arthroplasty system in accordancewith the disclosure showing a perspective view of a bone cut on ahumerus with a stem trial and shell trial and engagement pin;

FIG. 60 is a graphic of a step in the sequence of a representativeembodiment of a surgical technique for implanting an arthroplasty systemin accordance with the disclosure showing a perspective view of a bonecut on a humerus with a stem trial, shell trial and head trial in bone,and showing an exploded perspective view of a stem trial, shell trialand head trial;

FIG. 61 is a graphic of a step in the sequence of a representativeembodiment of a surgical technique for implanting an arthroplasty systemin accordance with the disclosure showing an exploded perspective viewof an assembly with representative surface features of a stem, a shell,and a head, and showing a perspective view of an assembled stem shelland head in bone with representative surface features;

FIG. 62 shows a humeral head cut approximately at the anatomical neck,with comparative views of circular (solid) and non-circular elliptical(transparent) heads.

FIG. 63 shows a humeral head cut approximately at the anatomical neck,with comparative views of non-circular elliptical (solid) and circular(transparent) heads.

FIG. 64 is a graphic depiction of a step in the sequence of arepresentative embodiment of a surgical technique for preparing a bonefor receiving a circular implant, showing a marking rendered on asubstrate, the marking representing the peripheral edge of a bone cut ona humerus, and showing a representative embodiment of a metaphysealshell; showing a marking rendered on a substrate, the markingrepresenting the peripheral edge of a bone cut on a humerus and analignment tool aligned therewith for central placement of a pilot hole;showing creation of a pilot hole in the representative bone; and showinga bit for creation of a concentric ring between the bone periphery andthe pilot hole;

FIG. 65 is a graphic depiction of a step in the sequence of arepresentative embodiment of a surgical technique for preparing a bonefor receiving a circular implant, showing a drilled concentric ringbetween the bone periphery and the pilot hole; showing placement of abone guard within the concentric ring that is between the bone peripheryand the pilot hole; showing an alternate view of a positioned bone guardwithin the concentric ring that is between the bone periphery and thepilot hole; and showing an alternate elongate bone guard for guiding areaming bit;

FIG. 66 is a graphic depiction of a step in the sequence of arepresentative embodiment of a surgical technique for preparing a bonefor receiving a circular implant, showing alignment of a reaming bit,such as a Forstner-style bit, with the pilot hole and within the boneguard for reaming the bone; showing positioning of an alternate elongatebone guard for guiding a reaming bit; and showing use of an alternateelongate bone guard for guiding a reaming bit;

FIG. 67 is a graphic depiction of a step in the sequence of arepresentative embodiment of a surgical technique for preparing a bonefor receiving a circular implant, showing use of an alternate elongatebone guard for guiding a reaming bit; showing a removed elongate boneguard and reaming bit for collection of bone material; and showingreamed bone; and,

FIG. 68 is a graphic depiction of a step in the sequence of arepresentative embodiment of a surgical technique for preparing a bonefor receiving a circular implant, showing a tapered bone reamer forrefined reaming of the bone hole and a representative metaphyseal shellfor placement in the bone hole; showing use of the taper reamer; showingthe prepared bone; and showing positioning of the representativemetaphyseal shell in the prepared bone.

DETAILED DESCRIPTION

This disclosure describes exemplary embodiments in accordance with thegeneral inventive concepts and is not intended to limit the scope of theinvention in any way. Indeed, the invention as described in thespecification is broader than and unlimited by the exemplary embodimentsand examples set forth herein, and the terms used herein have their fullordinary meaning.

The general inventive concepts are described with occasional referenceto the exemplary embodiments and the exemplary embodiments depicted inthe drawings. Unless otherwise defined, all technical and scientificterms used herein have the same meaning as commonly understood by one ofordinary skill in the art encompassing the general inventive concepts.The terminology set forth in this detailed description is for describingparticular embodiments only and is not intended to be limiting of thegeneral inventive concepts.

Modular and Convertible Shoulder Arthroplasty Components, Systems andMethods

Convertible Modular Arthroplasty Assembly

In various embodiments, a modular arthroplasty assembly is provided, andincludes implant components, instruments, trial components includingbroaches, trial convertible offset couplers, and trial humeral head andtrial cupped reverse prosthesis components, sizers, bits and guides, andfixation elements including adapters, screws, pins and wires. Further,in various embodiments, techniques for determining implant features andfor achieving implantation of modular arthroplasty assemblies areprovided.

Referring now to the drawings, FIG. 1 shows a side view of an embodimentof a modular arthroplasty assembly with a stem, assembled in the contextof shoulder bone.

In various embodiments, the modular arthroplasty assembly includes (a)an convertible offset coupler (also referred to herein as a “couplercomponent” and alternately a “metaphyseal shell”) bounded on a firstside by an implant surface adapted to receive an implant component, andbounded on an opposite second side by a bone anchor engagement surface,(b) an prosthesis component selected from one of a humeral head and acupped reverse prosthesis (also referred to herein as a “prosthesiscomponent” and alternately “head” and “cup,” respectively), and (c) abone anchor configured to be inserted in bone and adapted for engagementwith the convertible offset coupler (also referred to herein as a“anchor component” and alternately “stem” or “plug”). As shown in FIG.1, the implant component is a spherical shaped humeral head. FIG. 2shows alternate perspective views of an embodiment of a modulararthroplasty assembly with a stem and spherical head in the context ofbone, and FIG. 4 shows alternate back, front, perspective and side viewsof an embodiment of a modular arthroplasty assembly with a stem, showingan articulation surface in the form of a spherical head, a metaphysealshell and shell-stem locking pin, and stem.

It will be appreciated that for each of the possible components of themodular arthroplasty system, at least one or more size, shape and offsetoptions are available, and are selected from an array of sizes of heads(spherical and non-spherical), stems and plugs (of varying length,diameters, and width and depth dimensions, and metaphyseal shells ofvarious sizes (diameters) and offsets and engagement features forprostheses components. FIG. 3 shows an exploded side view of anembodiment of a modular arthroplasty assembly with a stem, showingrepresentative alternate stem lengths and representative alternatearticulation surfaces in the form of a spherical head and a concave polycup. Of course a wide range of possible combinations of components isavailable in accordance with the disclosure, and may be selected fromthe specific embodiments of arrays as disclosed herein and fromembodiments that are within the scope of the disclosure though notspecifically described in the specification and drawings.

While the above described drawings and the majority of other drawingsherein depict embodiments of the modular implant system that comprisestemmed arthroplasty systems, it will be understood and appreciated byone of ordinary skill in the art that other arthroplasty systems areknow, as described elsewhere in this disclosure, and that the modularsystem may be adapted to providing stemless systems for implantingprosthetic devices. FIG. 7-FIG. 10 show alternate views of such stemlesssystems, which encompass the use of bone anchors in the form of shortplugs, stems, and cages (generically referred to herein as “plugs”) witha variety of surface features and anchors and the like. These stemlesssystems may be provided in monolithic forms that are adaptations toallow for complete excision from bone in the event of revision surgery,and in alternate forms as modular systems in which one or all of theprosthesis articulation surfaces, metaphyseal shells, and anchors may beremoved for revision surgery. Plugs for stemless uses may be solid,hollow and may include screws, anchors, suture holes and surfacefeatures for optimizing press fit engagement within the metaphyseal boneand optionally at least a portion of the canal of the diaphysis. Incontrast to stems as described further herein, and which are intendedfor insertion of their distal portions within the diaphyseal canal andpress-fit of their proximal portions within the metaphysis, stemlessplug embodiments are press fit within the metaphysis without reliance onany stabilizing and anti-rocking protective function of the distalportion of a stem.

Convertible Offset Coupler (Metaphyseal Shell)

Referring again to the drawings, FIG. 5 and FIG. 6 show a representativeembodiment of a metaphyseal shell in accordance with the disclosure. Invarious embodiments, the overall shape of the metaphyseal shell isgenerally cylindrical, with an outer surface and dimensions that areadapted for insertion at least partially within humeral bone and isbounded on a first side by an implant surface adapted to receive animplant component, and on an opposite second side by a bone anchorengagement surface. In some embodiments, the metaphyseal is adapted withat least or one another of a male insert and a female receiver channel(such as a Morse type taper), on one or both opposing sides, andoptionally adapted to receive one or more of a pin or setscrew or otherfastener to achieve engagement with at least one of the prosthesiscomponent and the bone anchor. In some embodiments, the metaphysealshell bears on a lateral peripheral edge a surface feature that isadapted to enhancing boney ingrowth. Accordingly, in some embodiments,all or a portion of the outer surface of the metaphyseal shell may beadapted with surface texturing to encourage bone ingrowth or ongrowth.In addition, the stem engagement surface may be adapted with surfacetexturing to enhance engagement therebetween. In various embodiments,the metaphyseal shell includes at least one engagement feature thatallows engagement and fixation with each of the head and cup prostheses.In some embodiments, a metaphyseal shell is adapted with two or morehead and cup prosthesis engagement features. In other embodiments, ametaphyseal shell is adapted with one or the other of head and cupprosthesis engagement features.

Referring again to the drawings pertaining to the metaphyseal shell,FIG. 11-FIG. 15 show alternate views of a representative embodiment of ametaphyseal shell from the perspectives of the top (essentially superiorsurface), bottom (essentially inferior surface), side (essentiallylateral surface) and side cross section. Referring now to FIG. 12, whichshows various views, including a bottom view of an embodiment of ametaphyseal shell, in some embodiments, as depicted in the drawings, themetaphyseal shell includes a feature adapted for engagement with a boneanchor (stem or plug). As shown in the depicted embodiment, theengagement feature is in the form of a standard or Morse taper.According to various embodiments, the taper feature may be of varyinglength, and may be cylindrical or tapered. In various embodiments, theposition of the insert on the engagement surface may be varied. Forexample, the insert may be centered, or it may be offset from the centerat any of desirable selected positions to allow adaptability to therelative positioning of the engaged stem and metaphyseal shell.

Referring now to FIG. 15, which shows an array of sizes of arepresentative embodiment of a metaphyseal shell shown from the side,the top and the bottom, the position of the anchor engagement featuremay vary to provide an array of shells for selection to provide acustomized fit and engagement for a head or cup prosthesis. In thevarious embodiments, a metaphyseal shell with an offset for engagementwith an anchor is selected from offsets ranging in mm and incrementsthereof from 0 to 20 mm, and includes 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20. In some representativeembodiments, the range of offset may be from 0 to 10, and in somespecific embodiments, the offset may be from 0 to 6. Referring again tothe drawings, FIG. 15 shows an exemplary set of shells representingoffsets of 0, 1, 2, and 3 mm. It will be appreciated that any range ofoffsets may be provided, and that series of offsets on shells ofdifferent diameters and heights, as described herein below, may beprovided. In use, in a representative example of a modular arthroplastysystem, as depicted in the drawings, a shell is selected for its height,diameter, and engagement feature offset using tools for offsetmeasurement as described further herein below. The selected shell isplaced in the bone, its male taper engaged with the female taper of thestem; a set screw is inserted through the taper to engage themetaphyseal shell with the stem to secure the implant system inpreparation for engagement with the head or cup prosthesis.

As described herein, fixed engagement between the shell and anchor isachieved using a fixation element, such as, for example, a screw, setscrew or other fastener. Referring now to FIG. 14 which shows side viewsof alternate embodiments of a metaphyseal shell, including in crosssection, the shell is adapted with threading in a bore through theanchor engagement taper, the bore being threaded for receipt of a screw.A corresponding bore in the anchor, as shown in FIG. 17, is adapted forconcentric alignment with the through bore in the shell and likewise canreceive a screw. As shown in FIG. 4, a threaded locking pin or screw ispassed via threaded engagement through the two bores to secure and fixthe stem and shell together. It will be appreciated that the use ofsupplemental engagement means between the shell and the anchorcomponents is optional, and that in some embodiments the supplementalengagement means is not present, while in other embodiments, alternatesupplemental engagement means may be used. It will be appreciated by oneof skill in the art that a variety of fixation elements may be used toachieve fixation, including screws having continuous as well as variablethreading and other engagement means such as snap fit pins, expandablescrews and other fixation means known in the art. Likewise, thedimensions of such elements may vary in order to meet the length anddiameter requirements of the shell and stems to be engaged. The examplesshown herein are representative and are not limiting.

Referring again to FIG. 15, an array of sizes of a representativeembodiment of a metaphyseal shell is shown from the side, the top, andthe bottom. It will be appreciated by one of skill in the art that thespecific dimensions of metaphyseal shells may vary, depending on thebone receiving the shell. In the case of the humerus, the representativesizes of shell include a shell height (superior to inferior, or proximalto distal in the sense of articulation surface to bone surface) of about10 mm, which tapers proximal to distal in the manner of a Morse taperfor enhanced engagement with the bone. Representative FIG. 12 and FIG.14 show this taper feature as a generally frustoconical shape. Ofcourse, in alternate embodiments, such as shown in FIG. 11, the shapemay be frustohemispherical, or may have another shape that is eithercylindrical with flat sides or another shape with curved sides similarto those shown in FIG. 11. The peripheral profile of the shell willinfluence the surgical technique for preparing bone, and as such, thetechniques shown in this disclosure and as depicted in the drawings mayvary in order to prepare bone for receiving such alternate metaphysealshell shapes.

Referring again to FIG. 15, in accordance with the representative array,the diaphyseal shells vary in diameter from about 30 to 45 mm, moreparticularly from 34 to 40 mm, and in some specific embodiments includesizes that are 34, 36, 38 and 40 mm in diameter, respectively. Of courseother sizes and incremental portions thereof are possible, and can rangefrom 5 mm to more than 100 mm in diameter depending on the subject.Thus, shells may be provided in heights ranging in mm increments andfractions thereof from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68,69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86,87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 to 100, and indiameters in mm increments and fractions thereof from 5, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46,47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64,65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82,83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 to100.

Referring again to the drawings, FIG. 12 also shows perspective and topviews of an embodiment of a metaphyseal shell. The depicted metaphysealshell comprises an prosthetic implant engagement surface that isopposite from the stem engagement surface, and is adapted to receivevarious modular prosthesis components, such as a convex humeral headhaving a circular cross sectional shape or an elliptical shape whosepurpose is to articulate with a native glenoid or prosthetic glenoid, oralternatively a concave cup whose purpose is to articulate with aglenosphere, thus enabling the system to be used for either ananatomically correct shoulder prosthesis or alternatively a reverseshoulder configuration. In some embodiments, as shown in FIG. 12, andfurther detailed in FIG. 14, the metaphyseal shell is adapted with asubstantially cylindrical recess to receive insertion of a matingstructure on the prosthesis. So as to enable modularity, the implantsurface comprises at least one possible engagement feature, and in someembodiments two or more different engagement features, each of whichfeatures is adapted for engagement with different engagement structureson matable cups and heads.

As depicted, one engagement means is a taper, such as a Morse taper,adapted to mate with a corresponding structure on a prosthesiscomponent, such as the tapers shown on representative prosthesis headsshown in FIG. 30 and FIG. 31. In accordance with the representativearray of shells shown in FIG. 15, the dimensions of the engagementfeatures, including the representative taper feature, may vary in lengthand diameter, and in general, the dimensions of these features can rangefrom 5 mm to more than 100 mm. Thus, shells may be provided withengagement means, such as a taper, in heights and in greater and lesserdiameters ranging in mm increments and fractions thereof from 1, 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58,59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76,77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94,95, 96, 97, 98, 99 to 100 mm.

Another engagement means provided on a shell is circumferential tabs orteeth that enable a snap fit, such as for engagement with a cup as shownin FIG. 39 and FIG. 44. Such features may be present in singular or as aplurality, and may be positioned anywhere along the interior wall of themetaphyseal shell seat, including from the bottom to the top with anydesired spacing there between and other optional interspersed surfacefeatures that may enhance fixation of a prosthesis component therein.Representative drawings that show detail of some embodiments of theseengagement features are shown in FIG. 43 and FIG. 48, each of whichdrawings show side views of representative embodiments prosthesiscomponents with engagement means in the form of concentric teethpositioned at the base of a taper on each of the alternate cup shapedimplants. In some embodiments, the tabs or teeth may be notched toengage with corresponding splines or ribs to enable alignment andprevent axial displacement. Other means known in the art may be employedfor engagement between the metaphyseal shell and prosthesis. Inaccordance with the representative array, the dimensions of theengagement features, including the representative tab features shown inthe drawings, may vary in height and depth and spacing, and in general,the dimensions of these features can range from 0.1 mm to more than 20mm. Thus, shells may be provided with the depicted engagement means, inmm increments and fractions thereof from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6,0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,17, 18, 19, and 20 mm. Referring to the drawings, FIG. 12 and FIG. 13each show alternate views of metaphyseal shells adapted with differentengagement means which in the depicted embodiments are positioned at thebase of the recess in the shells adjacent to the interior sidewallsthereof. It will be appreciated that the various engagement means arenot intended to be limiting, and other engagement means that are notshown may be used, moreover, the engagement means may be used in thecontext of any form of prosthetic component, and may be usedinterchangeably between them.

In some embodiments, the shells include on their prosthesis surfacesother features that aid in placement and in removal. For example, one ormore slots or other access portals may be provided on a shell or plugcomponent to enable passage of an osteotome or other device tofacilitate freeing an implant from bone due to boney ingrowth thereupon.In addition, one or more circumferential tool engagement features suchas are shown on the upper periphery of the interior wall of themetaphyseal shell embodiments shown in FIG. 12, FIG. 13 and FIG. 14, maybe provided to aid in the placement and press-fit fixation of the shellinto bone, and subsequent adjustment or removal thereof in the event ofa revision surgery.

Referring now to FIG. 50, and FIG. 51, in some embodiments, a modularadapter referred to herein as an offset adapter may be provided thatoperates to mate the metaphyseal shell component with the humeral stemcomponent (specific engagement with the metaphyseal stem not shown). Anadapter may be in lieu of corresponding engagement elements on each ofthe metaphyseal shell and stem, or in addition to these. The modularityof the adapter enables further selection from a wide array of possiblecombinations of stem and metaphyseal shell positioning. In someembodiments, the shape of the adapter is configured for preciseengagement with the stem and metaphyseal shell components.

In some examples, one or both of the metaphyseal shell and stem may beadapted with a female receiver comprising a cylindrical recess and ashallower overlaid recess that is polyhedral in shape. In someembodiments, the overlaid recess is substantially rectangular. In someembodiments, the modular adapter component comprises a polyhedral insertbody having opposing faces, wherein each face has a male insert that issubstantially cylindrical or peg shaped. In such embodiments, theopposing male inserts are each adapted to be press-fitted into thefemale receivers respectively positioned in the metaphyseal shellcomponent and the humeral stem component, and the polyhedral insert bodyis received into the metaphyseal shell component. The modularity isachieved by varying the relative position of the opposing male inserts.

Accordingly, in various embodiments, an array of adapter components maybe provided wherein the male inserts are varied on position along theopposing faces of the adapter such that they may be positioned atopposite ends, directly opposed from one another on the same end of thepolyhedron or in the center, or at any other location along the opposingfaces. In this manner, a wide array of options is available to allowselection of optimal positioning of the metaphyseal shell componentrelative to the position of the humeral stem. In various embodiments,the male inserts may further be varied in length, diameter, andangulation relative to the face of the adapter. Accordingly, in variousembodiments, the modular adapter may have opposing male inserts thatvary from one another in one or more of shape, angulation relative tothe adapter face, length and diameter.

It will be appreciated that the metaphyseal shell is in some embodimentsadapted for use above the bone cut line, partially below the bone cutline, or as more particularly described and shown herein, countersunkessentially completely below the bone cut line. The advantages of themetaphyseal shell as described herein can be realized in any implantconfiguration whether above, or partially or fully recessed below thebone cut line, particularly to enable customized selection and fit ofimplant components without being constrained by inventory limitations orby less than desirable implant height, neck angle, version, andposterior and medial offset.

Humeral Stem Component

Referring again to the drawings, FIG. 16-FIG. 29 show a variety of viewsof representative bone anchors in the form of diaphyseal stems inaccordance with the disclosure. In various embodiments, the depictedshoulder prosthesis humeral stems are adapted for engagement with anmetaphyseal shell, and optionally with a complimentary intermediatemodular adapter component as described above. The humeral stem componentmay be used with the various modular adapter components described hereinin the manner described above to configure humeral stem with broadflexibility for relative positioning of the metaphyseal shell andprosthesis component relative to the stem.

Referring now to FIG. 16 which shows perspective views of an embodimentof a diaphyseal stem, the stem is comprised of a proximal region (aboutthe upper ⅓ of the stem) that is adapted for alignment with the bone cutin the metaphysis and engagement to the shell, and a distal region(about the lower ⅔ of the stem) which is fit into the distal region ofthe diaphysis. The proximal and distal ends are delineated in therepresentative drawings by a circumferential line positioned just abovethe elongate distal flutes, as seen in FIG. 19, for example. Alternatefront, back, side bottom (plan view from the distal end) and top (planview from the proximal end) are shown in FIG. 16-FIG. 20. In variousembodiments, the shape of one or both the proximal and distal ends ofthe stem are adapted to be press-fit within the bone. In certainexemplary embodiments, the proximal portion of the stem is selected tobe a best fit for tight press-fit within the upper diaphysis/metaphysisof the bone.

In various embodiments, the humeral stem includes an engagement feature,which is shown in representative FIG. 19 as a female taper receiver onits proximal end that is adapted to receive a male insert, such as atapered extension, to achieve engagement with the metaphyseal shell. Insome embodiments, the size, shape, location/position of the receiver andcombinations of these features may vary to allow adaptability to therelative positioning of the engaged stem and metaphyseal shell.

FIG. 23 shows alternate side, front and front cross-sectional views of arepresentative embodiment of a diaphyseal stem. Overall, the crosssectional shape of the stem at its proximal end is generally trapezoidaland is adapted for achieving a desirable degree of fill of the upper endof the diaphysis and the metaphysis. In various embodiments, based onthe size of the stem, the degree of fill to be achieved with a stemranges from 20 to 60%, and in some desirable embodiments about 40%.Thus, the extent of fill ranges from and includes as a percentage of thevoid space in the engagement area of the bone, about 20, 21, 22, 23, 24,25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42,43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, to60. Overall, the cross sectional shape of the stem at its distal end isgenerally circular and may be adapted with fluting or other features tofacilitate engagement of instruments for ease of removal as needed.

In some embodiments, the stem component is adapted to enhance bonyingrowth and bone strength at regions of the humeral bone, for exampleat the proximal end only of the stem. As shown in the drawings, forexample, FIG. 20, which shows a side view of an embodiment of adiaphyseal stem, in solid form, features on the proximal and distal endmay be included in some embodiments to facilitate fixation in the boneand facilitate subsequent removal, as in the instance of revisionsurgery. Again with reference to FIG. 20, according to some embodiments,the surface of the stem is configured with features and surfacetexturing to encourage bone growth along the proximal end of the stem,and the tapered distal end is devoid of texturing to discourage boneingrowth and to enable easy disengagement of the stem from the distaldiaphyseal portion in the event removal is necessary. In someembodiments, the entire lateral surface of the proximal end is texturedto encourage bone ingrowth. In alternate embodiments, such as shown inFIG. 16 and FIG. 27, for example, the stem has flattened panels on itssides and the flat areas of the proximal end are textured for bonyingrowth while the remainder of the lateral portions of the proximal endare not textured. Referring again to the drawings, FIG. 27 showsalternate side and perspective views of the shell engagement end(proximal end) and a bottom (distal end) view of a representativeembodiment of a stem. As shown, in some embodiments, the proximal endincludes one or more suture holes.

The length of the stem may be varied and its proximal and distaldimensions and features may likewise be varied in accordance with thoseknown in the art. FIG. 21 and FIG. 22 each show alternate depictions ofa size array of stems. FIG. 22 shows a side view of an array of sizes ofa representative embodiment of a diaphyseal stem. The array represents apossible set of stems that are provided in three lengths (short,standard and long) and varied sizes (in the depicted set, there are 8sizes) of proximal and distal features within the each length. FIG. 21shows a side view of an overlay of an array of sizes of a representativeembodiment of a diaphyseal stem at a particular length (short) showingthe variation in contour at the proximal end as a function of size. Inthe depicted embodiment of stem array, the girth of each stem size growsproportionally as the size increases, and the proximal and distalsections grow incrementally with size, with the distal length increasingat a greater rate relative to the proximal length. It will be apparentto one of ordinary skill that varying shapes and sizes of stems arepossible and generally within the skill in the art. In the context ofthe stems disclosed herein, the relative girth of the proximal end isselected to achieve the closest possible press fit within the bone toenhance stabilization, to provide maximal proximal surface contact tosupport the metaphyseal shell and to accommodate the fixation engagementbetween the shell and the stem. Thus, variations in stem features arepossible with respect to sizing, and the size without departing from thescope of the disclosure and the claims.

As shown in FIG. 22, the representative array includes the followingpossible set of stems: short stems that vary in length ranging fromabout 70 mm to 98 mm; standard stems that have a length of about 125 mm;and long stems that have a length of about 175 mm; Within each of theselengths, the stems further vary in size, with 8 representative sizes. Inaccordance with the foregoing, in various embodiments, the stems mayhave length dimensions as follows: The stems may vary in size from smallat a length of from 45 to 110 mm, and more particularly from about 60 to95 mm, and more particularly from about 60 to 95 mm; to a medium lengthfrom about 110 to 130 mm, and more particularly from about 125 mm; to along stem length from about 130 mm to about 180 mm, and moreparticularly from about 175 mm. Of course, multiple intermediate sizeincrements are possible, thus stems may vary in length in mm andincrements in between from about 45, 46, 47, 48, 49, 50, 51, 52, 53, 54,55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72,73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90,91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106,107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120,121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134,135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148,149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162,163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176,177, 178, 179, to 180.

In various embodiments, the stems may have proximal length dimensions asfollows: The proximal portions of the stems may vary in size from 35 to60 mm, and more particularly from about 40 to 54 mm. Of course, multipleintermediate size increments are possible, thus the proximal ends of thestems may vary in length in mm and increments in between from about 35,36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,54, 55, 56, 57, 58, 59, to 60.

In various embodiments, the stems may have distal length dimensions asfollows: The distal portions of the stems may vary in size small distallength of from 25 to 50 mm, and more particularly from about 30 to 44mm; to a medium distal length from about 70 to 90 mm, and moreparticularly from about 71 mm to about 85 mm; to a long distal stemlength from about 120 mm to about 140 mm, and more particularly fromabout 121 mm to 135 mm. Of course, multiple intermediate size incrementsare possible, thus the proximal ends of the stems may vary in length inmm and increments in between from about 25, 26, 27, 28, 29, 30, 31, 32,33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68,69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86,87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103,104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117,118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131,132, 133, 134 to 135.

The stems are provided to be suitable for placement within bone andengaged with a shell wherein the bone cut is at an angle of inclinationfrom and including angle increments in between 120, 121, 122, 123, 124,125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138,139, 140, 141, 142, 143, 144, and 145. In accordance with thedisclosure, in various embodiments, the stems have a shell-matingsurface having an inclination that is about 135 degrees. It will beapparent to one of ordinary skill in the art that the stems could beprovided having a different angle of inclination, and that the ultimateangle of inclination of an implant is determined based on the angleselected by the surgeon when making the bone cut.

In various embodiments, the stems may have a cross sectional shape thatis generally cylindrical, trapezoidal, rectangular or other, andcombinations of these between the proximal and the distal ends. And invarious embodiments, the stems may have circumferential dimensionfeatures in mm and increments in between from about 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43,44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79,80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97,98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112,113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126,127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140,141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154,155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168,169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182,183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196,197, 198, 199, to 200 or more.

Referring again to the drawings, representative images are showndepicting stems and shells of the disclosure engaged and engaged in thecontext of bone. FIG. 24, FIG. 25 and FIG. 26 each show, respectively,side, front, and front cross-sectional views of an selection of sizes ofa representative embodiment of a diaphyseal stem engaged with ametaphyseal shell, in the context of bone. These representations showthe variation of diaphyseal and metaphyseal bone contact achievedthrough stem selection. FIG. 28 shows a view of a selection of assembledrepresentative embodiments of a metaphyseal shell and diaphyseal stemshowing representative offsets to accommodate patient anatomy. FIG. 29shows a perspective view of two sizes of standard length diaphysealstems showing representative relative positions of the engagementreceiver (female taper) as the girth of the stem changes. As evident inthe drawing, the placement of the engagement feature appears shifted(front to back) as the girth of the proximal metaphyseal engagementportion of the stem increases. This design ensures that the engagementfeature of the shell with the stem is accommodated as the inner space ofthe bone is more constrained and the proximal end of the shell is moreslender to fit the anatomy.

Referring again to the drawings, FIG. 17 shows alternate cross sectionalviews of the depicted stem, showing further detail of the engagementfeature. As depicted, the feature is a female taper for receiving acorresponding taper on the shell, and is further adapted with asecondary fixation engagement feature in the form of a threaded bore. Asdescribed hereinabove, the engagement feature enables fixation betweenthe stem and the shell and likewise allows disengagement in the event ofdevice repositioning during primary surgery or removal and possiblereplacement in the event of a later revision. It will be appreciated, asmentioned herein above, that this exemplary secondary engagement featureis optional.

Referring again to FIG. 49, an alternate embodiment of a possible stemis shown that includes an anchor in the form of a modular diaphysealstabilizer that includes a stem. The depicted stem represents a shortstem that has a shorter length and extends less into the distal portionof the diaphyseal canal than the stems shown in the drawings FIG.16-FIG. 29, for example. As shown in FIG. 49, the stabilizer isgenerally elliptical or spherical in shape. In some embodiments, it maybe integrated with the stem and in other embodiments it may beremovable. The stabilizer may be selected from a range of stabilizersthat may vary in one or more of shape, length, diameter, and material.In some embodiments, the stabilizer as well as the distal portion of thestem is devoid of surface texturing or other material properties thatwould encourage bony ingrowth, while the more proximal portion of thestem may be in some embodiments be provided with material features toencourage bony ingrowth. The adjustability of the stem length and distalshape and diameter achievable with the modular stem and stabilizerprovides the ability to more closely customize the implant to aparticular patient, taking into account that older populations ofpatients tend to have diminished diaphyseal cortical bone and thus arelatively larger diameter medullary canal as compared with otherpatients. The stabilizer is desirable to provide distal stability to theimplant and prevent toggling at the proximal end, particularly at thetime just after implantation before bony ingrowth at the proximal endoccurs to enhance stability.

Prosthesis Component

In various embodiments, the modular arthroplasty assembly includes aprosthesis component. Examples of possible components, selected fromexemplary humeral head, FIGS. 30-31 and FIGS. 33-FIG. 38, and cuppedreverse prosthesis components, FIG. 39-FIG. 48. The prosthesis isadapted on a first surface to provide a functional feature, such as ahumeral head or a cupped reverse prosthesis function. On a second,generally opposing surface, the prosthesis comprises elements adaptedfor engagement with the metaphyseal shell. In some embodiments, theengagement is non-permanent such that the prosthesis component can bedisengaged from the metaphyseal shell through use of a tool adapted toachieve displacement.

Humeral Head Prosthesis

In some embodiments, the prosthesis component is a humeral headprosthesis. Referring again to the drawings, FIGS. 30-31 and FIG.33-FIG. 38 show various aspects of humeral heads that may be used inaccordance with the disclosure. The particular features of overallshape, and dimensions may be selected from those examples generallyknown in the art. For example, spherical shaped components may beselected, and the component may comprise essentially a full sphere, or ahemisphere, or some greater or lesser fraction thereof. In someembodiments, the shape of the humeral head prosthesis is generallyelliptical but non-spherical, allowing an enhanced selection to achieveanatomical matching between the removed native humeral head and theprosthesis. In accordance with the disclosure, use of heads that have anon circular elliptical cross section are particularly desirable forproviding the widest array of options to replicate native anatomy and toavoid functional problems for the patient with the arthroplasty. Asdescribed further herein below, use of such heads that have a noncircular elliptical cross section together with the novel metaphysealshell coupler component enables the surgeon to accommodate not onlyoffsets in positioning from the AP and SI planes, but also rotationalpositioning of the heads that have a non circular elliptical crosssection to achieve the most desirable replacement anatomy. Referring tothe drawings, FIG. 62 and FIG. 63 show alternate comparative views ofhumeral heads cut approximately at the anatomical neck, each with solidand transparent alternate heads. These drawings illustrate the variableresults obtained with an arthroplasty based on selection of a circularvs. non-circular elliptical head. FIG. 62 shows a spherical head insolid overlaid with an elliptical head in transparent to illustrate thata spherical head that is selected for suitable fit in the AP directionwould be undersized in the SI direction. FIG. 63 shows an ellipticalhead in solid overlaid with spherical head in transparent to illustratethat a spherical head that is selected for suitable fit in the SIdirection would be oversized in the AP direction, which arrangementcould cause rotator cuff tearing and joint stiffness. Thus, while thedisclosure encompasses embodiments that include selection of heads thathave a circular elliptical cross section, particularly good results canbe obtained selecting heads that have a non circular elliptical crosssection when used in conjunction with the novel anatomical positioningenabled with the coupler components herein.

In the various embodiments, head prostheses have dimensions that aresuited to allow a range of custom fits to a subject's anatomy. As such,heads vary in terms of shape (round to elliptical), height (distancefrom the surface engagement with the shell to the apex), and peripheraldimension (circumference for round heads and AP to SI dimensions forelliptical heads). In accordance with what is known in the art, theoverall shape of the heads at the apex is generally spherical, thoughthe scope of the invention includes use of heads that may have anothershape as may be available in the art. In the case of elliptical headsherein, it is contemplated that such heads having spherical apexes wouldpresent a glenoid articulation surface that is spherical and would taperalong the SI dimensions to the periphery along a generally ellipticalarc. It will be appreciated that practice of the invention, particularlywith reference to the novel operation of achieving proper offset with ashell to mate a stem with a head or cup, that the shape and size of ahead or cup is not limiting.

As described herein, the SI and AP dimensions of a humeral headaccording to the disclosure are in reference to a cross sectional planeof a humerus essentially in the AP plane with an inclination angle offthat plane from about 120 to 145 degrees, and in some embodiments from120 to 143, and in certain disclosed embodiments herein, of about 135degrees. The cut corresponds to the anatomical neck of the humerus seeURL (//en.wikipedia.org/wiki/Anatomical_neck_of_humerus).

Referring again to the drawings, FIG. 37 shows an exemplary array ofelliptical heads that vary in size as follows relative to a bone cut onthe AP plane: range from 30 mm to 62 mm in the superior to inferiordimension, and range from 30 to 58 mm in the anterior to posteriordimension. In some particular embodiments, the SI range is from 37 to 56mm and the AP range is from 36 to 51 mm. In yet other embodiments, theSI range can encompass from 20 to 80 mm, and can include sizes in the SIdimension from and including the following and increments in between:20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73,74, 75, 76, 77, 78, 79, 80 mm. Likewise, in such other embodiments, theAP range can encompass from 20 to 80 mm, and can include sizes in the SIdimension from and including the following and increments in between:20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73,74, 75, 76, 77, 78, 79, 80 mm. Selection of the specific size will bemade in accordance with the skill in the art and with particularreference to the size and population features of the subject.

In one representative embodiment of an array of elliptical heads,included head sizes may encompass the following array, wherein the APdimension ranges from 36 to 51 mm, the SI dimension ranges from 37-56mm, the ratio of AP/SI ranges from 0.87 to 1, and wherein the angle ofinclination ranges from 120 degrees to 143 degrees. Specific headswithin the array are provided in sizes having head heights ranging from12 to 25 mm, and in representative embodiments from 14 to 21 mm, and incertain specific embodiments in increments there between.

The relationship between the SI to AP dimensions in one embodiment ofelliptical heads is 1 (spherical heads), as shown in representative FIG.35. In an alternate embodiments, the SI to AP dimensions are related ina range where the SI dimension is a constant of about 2 mm larger thanthe AP dimension regardless of head size. In alternate embodiments, theconstant of variation between the SI and AP dimensions may vary from 0.5mm to 10 mm or more, and thus can include constant variation in mm andincrements in between including 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mm,as shown in representative FIG. 38. In yet another alternate embodiment,the SI to AP dimensions are related in a range where the AP/SI ratiochanges from 1 to 0.85 as the head size increases. Generally, accordingto such embodiments where the AP/SI ratio changes, the range can includefrom 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, and 2 and incremental fractionsthere between.

Cupped Reverse Prosthesis

In some embodiments, the prosthesis component is a cup for placement onthe humeral bone in the context of a reverse arthroplasty, and thepurpose of which is to articulate with a glenosphere implanted in thescapular. Referring again to the drawings, FIG. 39-FIG. 48 show variousaspects of cups that may be used in accordance with the disclosure. Aselection of cups may be offered with varying curvatures, pitches, andheights to achieve the anatomical configuration desired by the surgeonfor any particular patient. The cup may be formed of a polymer, carbon,or metal or combinations of these, or may be formed of or coated with amaterial that aids in preventing spalling to avoid osteolysis that isassociated with polymer wear and spalling with cupped reverse prosthesiscomponents commonly used in shoulder arthroplasty. In accordance withthe various embodiments, the cup is generally cylindrical in shape andmay in some embodiments have a modest taper from the top (bearingsurface) to the bottom (the shell engagement surface). The bearingsurface is concave and essentially spherical in curvature, and thebottom, shell-contacting surface, is essentially planar and adapted torest on the interior face of the shell. In various embodiments, the cupbears on its lateral circumferential surface engagement means forfixation with the shell. According to certain embodiments, theengagement means include circumferential tabs or teeth as shown indetail in exemplary embodiments shown in FIG. 48 and FIG. 49 that enablea snap fit with corresponding and complimentary structures on the innerwall of the shell as shown in detail in exemplary embodiments shown inFIG. 12 and FIG. 13. The tabs or teeth may be notched to enablealignment and prevent axial displacement, and may include a singlestructure such as shown in FIG. 48, for example, or may include aplurality, as shown in FIG. 49, for example.

Thus, in accordance with various embodiments comprising more than twoengagement structures, the spacing there between may be the same orvaried. The engagement features on the cup may be positioned at anylocation from the top to the bottom wherein corresponding andcomplimentary features are likewise positioned within the engagementwall of the shell. Representative embodiments of engagement features areshown on the shell in FIG. 11, and on the cup in FIG. 39-FIG. 43,wherein the feature comprises on the shell a single circumferentialtooth positioned at the bottom of the internal edge adjacent with theseat of the shell and wherein the feature comprises on the cup a singlecircumferential tooth positioned at the bottom of the lateral edgeadjacent with the bottom edge. Alternate representative embodiments ofengagement features are shown on the shell in FIG. 12, and on the cup inFIG. 44-FIG. 48, wherein the feature comprises on the shell a pair ofcircumferential teeth positioned at the bottom of the internal edgeadjacent with the seat of the shell and wherein the feature comprises onthe cup a pair of circumferential teeth positioned at the bottom of thelateral edge adjacent with the bottom edge. It will be appreciated bythose of skill in the art that the number, position and type ofengagement means may be varied in accordance with the skill in the artand that other snap fit type features may be selected for achievingengagement between the shell and the cup.

Modular Humeral Implant (Stemless)

In various embodiments, as shown in FIG. 7-FIG. 10, the disclosure alsoprovides a modular and modular arthroplasty assembly includes (a) astemless humeral implant configured to be inserted in a humerus andintegrated with or adapted for engagement with an metaphyseal shell thatis bounded on a first side by an implant surface adapted to receive animplant component and (b) a prosthesis component selected from one of ahumeral head and a cupped reverse prosthesis. The stemless humeralimplant includes a plug shaped anchor component (“plug”) that may be, invarious embodiments, solid or hollow and may be optionally threaded,wherein the thread profile and pitch may be selected from those known inthe art, for example square threads. The stemless humeral implant alsoincludes a bone engagement rim that extends below the plug for enhancedbone engagement. In various embodiments, either or both the plug and rimmay be threaded, wherein the thread profile and pitch may be selectedfrom those known in the art, for example square threads, and may befenestrated to promote bone ingrowth.

In various embodiments, the methods for implant of the wherein thethread profile and pitch may be selected from those known in the art,for example square threads include surgical techniques wherein one orboth the stemless humeral implant and the metaphyseal shell arecompletely or partially recessed within the humeral bone. According tothe various embodiments, placement of one or both the stemless humeralimplant and the metaphyseal shell within the bone (i.e., below the cutline) allow a greater range of options with respect to establishing thedesired center of rotation in the shoulder joint.

Bone Preparation to Receive Metaphyseal Shell

There is a lack of disclosure in the art for preparation of bone toreceive a circular implant, particularly in the case of subjects in whomthere is weak or compromised bone. It is know that the cavitary regionin the metaphysis enlarges with age. Once the head of a humerus or otherlong bone is resected, it is difficult to ream over a pin because poorbone quality precludes solid fixation of the pin. Thus, it is desirableto implement techniques for bone preparation that protect the bone. Inaccordance with meeting this need, provided is a representativetechnique for preparation of bone to receive a partially or fullyrecessed metaphyseal shell:

Referring again to the drawings, FIG. 52 and the subsequent drawingsincluding specifically FIG. 64 through FIG. 68 show images of steps andalternate steps for bone preparation, which include the steps asfollows:

Identify center point of bone; Create pilot hole with drill; Use holesaw to make circular hole (this saw is easy to control and keep centeredbecause it removes little bone); a humeral head protector is placed inthe circular hole—the fixation for the humeral head protector is solidsuch that during surgical exposure of the glenoid as the surgeon leverson the proximal humerus this device keeps the proximal bone from beingcrushed; if the surgeon wishes, the humeral head protector may be usedto guide a Forstner-style bit, and the walls of the protector help thesurgeon to better control the trajectory of the bit, which may beotherwise hard to control. Optionally, for enhanced control and to limitthe depth of reaming, a “top hat” tubular structure may be used, whichthe surgeon may choose to stabilize this with his/her fingers; aForstner-style bit that serves to ream the bone may have a cylindercoupled to it for the purpose of collecting bone graft; the bit isremoved and bone graft is collected and prevented the bone graft fromspilling into the surgical field; a clean, large-diameter hole withvertical walls has been created, which is further tailored using alarger diameter of the reamer where the vertical walls of the hole serveto center the reamer; a reamer that is shaped similar to the finalprosthesis is used to enlarge the proximal, but not distal, aspect ofthe hole; the hole is ready to accept the final prosthesis, which isperfectly centered within the outline of the centering tool;

Surgical Technique with Modular Convertible Components

In various embodiments, the surgical technique involves access to theproximal humerus bone for removal of the native humeral head andreplacement with a modular arthroplasty assembly in accordance with thedisclosure. FIG. 52 shows a graphic depiction of steps of arepresentative embodiment of a surgical technique for implanting anarthroplasty system in accordance with the disclosure.

The specific order of the steps outlined herein below are not intendedto be limiting, and not only may the order be varied, but additionalsteps may be included and certain steps may be eliminated based on thespecifics of the anatomy and other factors.

The humeral head is surgically accessed;

The anatomical neck of the humerus is cut (for example, at approximately135 degrees based on the native anatomy, or at such other angle as maybe determined by the surgeon with or without a cut guide) and the nativehumeral head is removed;

A trial humeral head “sizer” or guide is positioned on the proximalhumerus bone cut, the sizer being anatomically shaped like the intendedprosthesis heads; the desired size and orientation are determined; thetrial head sizer will have a central hole in it;

After proper size and orientation of trial humeral head have beendetermined, the sizer is fixed in place and a pin is drilled through thecenter hole in the sizer; the sizer head is removed from over the pin,leaving the pin in place (a K-wire may be used);

A reamer that is size dimensioned to match the size and shape of themetaphyseal shell is selected and placed over the central pin (forexample, the size of the metaphyseal shell and corresponding reamer isselected from a set of reamers with dimensions ranging from 30 to 60mm); the reamer is operated to form a recess cavity in the bone toaccommodate the metaphyseal shell (the “metaphyseal shell seat”);

A broach/trial prostheses for the humeral stem is selected to find theaxis of the diaphysis; starting with the smaller diameter broaches, thebone is trialed and the broaches exchanged for those increasing in sizeuntil a trial is identified that provides a snug fit; the trial broacheswill be shaped like the diaphyseal portion of the humeral stem portionof the implant;

Optionally, an alternate or second broach/trial for the stem is selectedto determine stabilizer size, shape and length to most closely match theanatomy; starting with the smaller diameter stabilizer broaches, thebone is trialed and the broaches exchanged for those increasing in sizeuntil a trial is identified that provides a snug fit distally and to adepth that is desirable for the humeral stem portion of the implant;

A feature such as a graduated line or plate or other indicator on thebroach handle is used to determine the depth of the broach to achievealignment of the proximal end of the stem with the bottom of themetaphyseal shell recess (i.e., alignment of the top/proximal surface ofthe stem with the surface line of the bone in the metaphyseal shellseat); once a snug fit has been achieved, the broach handle is removed;the desired broach depth will provide positioning of the location of thefemale taper of the broach/trial stem, and a correspondingly sized trialstem is inserted in the bone, and a size guide is positioned over themetaphyseal shell bone cut to determine offset positioning for the maletaper of the metaphyseal shell with the female channel of the stem;

A metaphyseal shell with the appropriate offset for engagement with thestem is selected (offset examples include 0, 2, 4, or 6 mm of offset)and placed in the bone, its male taper engaged with the female taper ofthe stem; a screw is inserted or another coupling device is utilized toengage the trial metaphyseal shell with the broach/trial stem tocomplete the trial implant system;

A trial prosthesis is selected, such as from a humeral head or reversearthroplasty cup prostheses;

The trial implant is removed, the screw or other coupling device willhave locked the orientation of the metaphyseal shell relative to thestem and indicators on the metaphyseal shell (for example, numbered 1-12to indicate position, like the face of a clock) will provide a key forthe surgeon as to how to assemble the final components for implantation(e.g., from the trial components an indicator #3 on the metaphysealshell may align with a particular marker indicator on the proximal endof the stem, so the final component is then assembled to match theseindicators), using the sizes of metaphyseal shell and stems as selectedwith the trials with a predetermined size enhancement (dimensionsslightly greater than the trial, as predetermined) to ensure a tightpress fit into the bone;

The full implant is assembled on the bench, and then press fit into thebone such that all or substantially the entire metaphyseal shell isbelow the bone surface, and so that all or substantially the entire stemis below the bone surface at the base of the metaphyseal shell seat;

It will be appreciated that the above technique may be varied, and thatthe components described are merely exemplary, and features size asengagement means, as well as dimensions, and engagement indicators andgauges may be varied, and are thus non-limiting;

Determining Offset Positions of Prosthesis Components

In various embodiments, the surgical technique involves access to theproximal humerus bone for removal of the native humeral head andreplacement with a modular arthroplasty assembly in accordance with thedisclosure. The specific order of the steps outlined herein below arenot intended to be limiting, and not only may the order be varied, butadditional steps may be included and certain steps may be eliminatedbased on the specifics of the anatomy and other factors. Instruments andthe technique referred to herein are shown in the drawings, FIG. 52shows a graphic depiction of steps of a representative embodiment of asurgical technique for implanting an arthroplasty system in accordancewith the disclosure.

FIG. 53 shows a graphic of a step in the sequence of a representativeembodiment of a surgical technique for implanting an arthroplasty systemin accordance with the disclosure showing a side view of a humerus and acut line for excision of a portion of the humeral head. According to thesurgical technique, the humeral head is surgically accessed and theanatomical neck of the humerus is cut (for example, at approximately 135degrees based on the native anatomy, or at such other angle as may bedetermined by the surgeon with or without a cut guide) and the nativehumeral head is removed;

A trial humeral head “sizer” or guide is positioned on the proximalhumerus bone cut, the sizer anatomically shaped like the intendedprosthesis heads; the desired size and orientation are determined; thetrial head sizer will have a central hole in it;

After proper size and orientation of trial humeral head have beendetermined, a mark is made on the bone that correlates with a marker atthe 12 o'clock position on the trial sizer head, the sizer is held inplace and a pin is drilled through the center hole in the sizer; thesizer head is removed from over the pin, leaving the pin in place (aK-wire may be used);

A reamer that is size dimensioned to match the size and shape of themetaphyseal shell (line to line) is selected and placed over the centralpin (in some examples the size of the metaphyseal shell andcorresponding reamer is selected from dimensions from 30 to 60 mm, andmay be in some examples 40 mm or 35 mm); the reamer is operated to forma recess cavity in the bone to accommodate the metaphyseal shell (the“metaphyseal shell seat”);

A broach/trial prostheses for the humeral stem is selected to find theaxis of the diaphysis; starting with the smaller diameter broaches, thebone is trialed and the broaches exchanged for those increasing in sizeuntil a trial is identified that provides a snug fit; the trial broacheswill be shaped like the diaphyseal portion of the humeral stem portionof the final implant and in some embodiments there is a plate on thebroach handles to control depth and to check for proper orientation;

Optionally, an alternate or second broach/trial for the stem is selectedto determine stabilizer size, shape and length to most closely match theanatomy; starting with the smaller diameter stabilizer broaches, thebone is trialed and the broaches exchanged for those increasing in sizeuntil a trial is identified that provides a snug fit distally and to adepth that is desirable for the humeral stem portion of the implant;

A feature such as a graduated line on the broach handle is used todetermine the depth of the broach to achieve alignment of the proximalend of the stem with the bottom of the metaphyseal shell recess (i.e.,alignment of the top/proximal surface of the stem with the surface lineof the bone in the metaphyseal shell seat); once a snug fit has beenachieved, the broach handle is removed; the desired broach depth willprovide positioning of the location of the female taper of thebroach/trial stem, and a correspondingly sized trial stem is inserted inthe bone, and a size guide is positioned over the metaphyseal shell bonecut to determine offset positioning for the male taper of themetaphyseal shell with the female channel of the stem;

Once a snug fit has been achieved, the broach handle is removed and afemale taper of the broach/trial stem can be seen; an offset instrumentfor the metaphyseal shell is used, the instrument having a generallycircular profile and an index feature at its center and a long handlewhereby the generally circular portion is inserted into the preparedcavity as shown in representative FIG. 56-FIG. 58, the posterior offsetamount is recorded, and using markings on the instrument, themetaphyseal shell-to-stem, and metaphyseal shell-to-head positions areidentified and recorded. Referring now to FIGS. 56 and 57, arepresentative embodiment of an offset tool is shown. In one embodimentof use, the trial shell (disc shaped with a central recess) is insertedinto the prepared bone and rotated such that the hole in the base of thetrial shell aligns with the female receptacle in the stem/broach(previously placed); the taper/gauge (elongate member with proximal gripand distal substantially square shaped engagement feature) is insertedthrough the central hole in the shell so that it engages the femalereceptacle in the stem/broach to achieve proper alignment of both shelland taper relative to the bone and stem/broach, and the offset readingsfor shell offset and rotational orientation are recorded using theexemplary markings.

Referring again to the drawings, FIG. 58 shows an alternaterepresentative embodiment of an offset tool that includes, as shown,positional 1-12 markings that correspond to conventional analog clocknumber positions, (it will be appreciated that other indicator featuresmay be used and the selection of an analog clock marking features is notintended to be limiting, and any other indictors and marks, whethercomprising letters, numbers, symbols and combinations of these may beused);

A metaphyseal shell with the appropriate offset for engagement with thestem is selected (offset examples include 0, 2 and mm of offset, forexample: 0, +2, +4, +6, +8) and placed in the bone, its male taperengaged with the female taper of the stem; a set screw is inserted toengage the trial metaphyseal shell with the broach/trial stem tocomplete the trial implant system and the position of the metaphysealshell relative to the bovie line can again be recorded;

The etched marking is aligned with the mark on the bone, the trialhumeral prosthesis is selected and engaged with the metaphyseal shell tocomplete the trial prosthesis;

The trial implant is removed, the screw will have locked the orientationof the metaphyseal shell relative to the stem and indicators on themetaphyseal shell (for example, numbered 1-12 to indicate position, likethe face of a clock) will provide a key for the surgeon as to how toassemble the final components for implantation (e.g., from the trialcomponents an indicator #3 on the metaphyseal shell may align with aparticular marker indicator on the proximal end of the stem, so thefinal component is then assembled to match these indicators), using thesizes of metaphyseal shell and stems as selected with the trials with apredetermined size enhancement (dimensions slightly greater than thetrial, as predetermined) to ensure a tight press fit into the bone;

The full implant is assembled using the pre-recorded positions foroffset, metaphyseal shell-to-stem, and metaphyseal shell-to-head of thetrial prosthesis; the final prosthesis being slightly larger than thetrial prosthesis in order to achieve a press fit;

Finally, the implant is press fit into the bone such that all orsubstantially the entire metaphyseal shell is below the bone surface, sothat all or substantially the entire stem is below the bone surface atthe base of the metaphyseal shell seat;

It will be appreciated that the above technique may be varied, and thatthe components described are merely exemplary, and features size asengagement means, as well as dimensions, and engagement indicators andgauges may be varied, and are thus non-limiting.

Exemplary Surgical Preparation and Implantation of Humeral ModularAssembly

In yet another particular embodiment, the following surgical techniqueis used for implantation of a shoulder prosthesis;

Humeral Head Osteotomy:

Using a humeral head cut guide, Resect humeral head at about 135 degreesof inclination;

Humeral Head Sizing and Orientation:

Select an optimally sized, anatomic pin guide. Record the size selected.Position guide flat on the humeral head cut with the etchedmedial-lateral orientation-markers at the most superior and inferiorlocations of the cut (the 12 and 6 positions on the face of the cut);

Alignment Pin Placement:

Once optimal size and orientation are achieved, using a bovie, mark thelocation of the superolateral orientation marker on the superior aspectof the greater tuberosity. Holding the anatomic pin guide in properorientation, under power, pass an alignment pin through the cannula andinto the proximal humerus to a depth at the level of the lateral cortex.Remove anatomic pin-guide and record humeral head size for trial headand definitive implant selections;

Metaphyseal Preparation:

Select the optimally sized 30-44 mm cannulated metaphyseal reamer. Allowenough peripheral bone to accommodate an additional 2 mm of proximalhumeral bone displacement for optimal press-fit fixation of thedefinitive metaphyseal shell. Pass the cannulated metaphyseal reamerover the alignment pin. Under power, ream the humeral metaphysis to apositive-stop;

Diaphyseal Preparation:

Assemble modular impaction handle and broach/compactor (TBD) stem. Alignthe superolateral alignment marker on the modular impaction handle withthe superolateral reference marker on the greater tuberosity (created inStep 2). Sequentially broach/compact diaphysis to a positive-stop (atthe level of the broach/compactor metaphyseal shell) until cortical bonecontact is achieved. With the definitive broach/compactor fully seated,release the modular impaction handle, leaving the broach/compactor stemin place to serve as the trail stem;

Determining Metaphyseal Shell Offset:

Select the appropriately sized (30-44 mm) metaphyseal shell offset guideand insert into reamed metaphyseal cavity until the distal portion ofthe metaphyseal shell offset guide is fully seated on reamed surface.Rotate the metaphyseal shell offset guide until the distal offset rulerbisects the center of the female Morse taper. Record the amount ofposterior offset (1 mm to 12 mm) required for optimal metaphyseal shellorientation. Prior to removing the metaphyseal shell offset guide; usethe greater tuberosity reference indicator (created in Step 2) and theouter positioning dial of the metaphyseal shell offset guide, record theoptimal rotational position for the metaphyseal shell;

Trial Metaphyseal Shell Placement:

Referencing the measurements recorded off of the metaphyseal shelloffset guide in Step 6, select the appropriate sized (30-44 mm)metaphyseal shell trial with the optimal amount of offset (0, +1, +2,+4, +8). Align the rotational position indicator of the trialmetaphyseal shell (recorded in Step 6) with the greater tuberosityreference mark. Introduce the metaphyseal shell trial until the maletaper is fully seated into the female table of the trial stem. Introduceand fully seat the trial metaphyseal shell set screw to ensure a securehumeral trial assembly. Record the definitive position of themetaphyseal shell using the rotational reference dial and greatertuberosity superolateral indicator mark;

Trial Head Positioning and Assembly:

Select the humeral head trial that corresponds to optimally sizedanatomic pin guide (recorded in Step 3). If optimal humeral head cutcoverage is not initially achieved, select a larger or smaller diametertrial as needed. Align the trial humeral head orientation markers withthe superolateral marking on the greater tuberosity. Insert the humeralhead trial into the metaphyseal shell trial until fully seated. Lightlyimpact the humeral head trial until rotational stability is achieved;

Definitive Implant Assembly:

Remove the trial prosthesis, fully assembled, such as with a threadedslap hammer. Referencing the trial stem to trial metaphyseal shellorientation markers and the trial metaphyseal shell to trial humeralhead orientation markers, orient and assemble the definitive humeralcomponents in their optimal anatomic positions. (As defined by the trailhumeral prosthesis);

Surgical Technique for Revision Surgery Using Modular ConvertibleComponents

In various embodiments, the surgical technique for a revision surgeryafter initial implantation of the modular arthroplasty assembly involvesaccess to the proximal humerus bone. Once accessed, the originalprosthesis is removed and replaced with a new prosthesis of either thesame type, or another type. For example, the revision may involvereplacement of a humeral head prosthesis with another humeral headprosthesis. Or the revision may be to achieve a reverse shoulder, inwhich case the humeral head prosthesis is replaced with a cupped reverseprosthesis. The specific order of the steps outlined herein below arenot intended to be limiting, and not only may the order be varied, butadditional steps may be included and certain steps may be eliminatedbased on the specifics of the anatomy and other factors;

The humeral head is surgically accessed;

A saw or other suitable tool is used to remove any superficial bonygrowth from the edge and outer surfaces of the prosthesis;

A suitable tool is used to disengage the prosthesis, optionallyaccessing available osteotome slots as needed;

Optionally, the metaphyseal shell is removed and a replacementmetaphyseal shell is positioned by press fitting to accommodate areplacement prosthesis wherein the replacement shell may include one ora combination of a different circumferential size, a different offset,and different prosthesis engagement features for engagement with a heador a cup, as needed;

A replacement prosthesis is selected and engaged with the metaphysealshell;

Other surgical steps are taken to complete the surgery;

Shoulder Arthroplasty Trials and Instruments

In exemplary embodiments, trials for exemplary embodiments of prosthesescomponents are provided herein, the representative embodiments shown inFIG. 60 are trial humeral heads. This disclosure also contemplates andprovides exemplary instruments to achieve shoulder arthroplastyprocedures in accordance with the inventive components and techniquesherein. Disclosed herein are representative instruments including trialhumeral head “sizer” or guide instrument, a stem trial broach handlewith depth indicator or guide, and a metaphyseal shell offsetinstrument. In the exemplary embodiments described herein and shown inthe drawings, the instruments have features to enable custom implantselection and positioning.

In exemplary embodiments, trials for the metaphyseal shell are providedherein. The trials are adapted for engagement with a trial or long bonestem prosthesis component, such as a humeral stem according to variousembodiments disclosed herein, and with a trial or prosthesis component,in some examples selected from the humeral head and cupped reverseprosthesis prostheses disclosed herein. An exemplary embodiment of ametaphyseal shell trial is shown in FIG. 70, wherein the trial has aneccentrically positioned male tapered coupler for engagement with afemale tapered receptacle on a corresponding stem component, and thetrial bears markings identifying its offset position to ensure customfit alignment of the shoulder implant components within the humerus of apatient. In working embodiments, a selection of metaphyseal shell trialsis provided, each with different offsets, and bearing markings forindication of offset and positioning of an implant prosthesis component(for example head or cupped reverse prosthesis).

Of course, it will be appreciated by one of ordinary skill that thescheme of markers and selection of indicators on the shell positioningtools may be varied without departing from the scope of the invention.

One exemplary offset instrument for the coupler component metaphysealshell is shown in FIG. 56 and FIG. 57. According to this embodiment, theoffset measurement tool is shaped according to the selected shape of theshell implant, in the depicted embodiments in FIG. 56 and FIG. 57 asfrustoconical. The shell includes a cut out in its center withpositional indicators in the form of metered markings, and an insertiontool that fits through the cut out and is adapted with an engagementfeature to engage with a placed stem trial. In use, the trial shell isinserted into the prepared bone and rotated such that the hole in thebase of the trial shell aligns with the female receptacle in thestem/broach, the insertion tool is inserted through the central hole inthe shell so that it engages the female receptacle in the stem/broach toachieve proper alignment of both shell and taper relative to the boneand stem/broach, and the offset readings for shell offset and rotationalorientation are recorded using the exemplary markings.

In an optional additional embodiment of use, the modular trial shell mayinclude a screw or other fixation element that passes through thetaper/gauge insertion tool and locks into the broach/stem enabling theentire assembly of the trial anchor and trial shell to be used as both atrial prosthesis as well as a measuring device—saving steps as well asinventory. In this embodiment, the inventory can be reduced byeliminating trial shells each with different offsets and thus have dualpurpose tool that achieves the offset measurement and is provided in thedesired array of sizes selected from, for example, 34, 36, 38, and 40mm.

An alternate offset instrument for the metaphyseal shell, as shown inrepresentative embodiments in FIG. 58, has an offset dial that isgenerally circular in profile and substantially matches the profile ofthe metaphyseal shell and is adapted for easy insertion in the reamedbone to approximate the metaphyseal shell. The offset dial includes anindex feature at its center, a dial etched around its periphery, and along handle whereby the generally circular offset dial is inserted intothe prepared bone cavity as shown in representative FIG. 58. This singleinstrument can be used to establish any superior to inferior andanterior to posterior offset needed between the center of themetaphyseal shell and the anchor and the rotational orientation of thehead. Of course, other tools and methods may be used to measure theseoffset and rotational features. In use, the offset is recorded relativeto the position of the female taper in the stem trial to enableselection of the appropriate metaphyseal shell. Using markings on theinstrument, such as for example the shown 1-12 markings that correspondto conventional analog clock number positions, the metaphysealshell-to-stem, and metaphyseal shell-to-head positions are identifiedand recorded to allow for optimal anatomical positioning of the implantprosthesis during its implantation. Of course, it will be clear to oneof ordinary skill that the instrument may vary in material, length, andimplements for guiding insertion of the offset dial with the bone cut,and as such, the exemplary embodiment is merely representative. Inalternate embodiments, the offset dial may have other index featuresthat aid in establishing appropriate offset of the metaphyseal shellrelative to the stem and the head. Likewise, any of a variety of handlefeatures and configurations known in art may be utilized to facilitatehandling and positioning of the instrument relative to the stem andhumerus.

In exemplary embodiments, trials for the humeral stem component areprovided herein. Representative embodiments are shown, for example, inFIG. 52. Their use with other trial and prosthesis components andarthroplasty instruments are described herein below in connection withexemplary surgical techniques. The disclosed trial humeral head sizerinstrument has a generally circular shape and domed profile with acannulated and knurled handle for ease of positioning and placement ofthe K-wire/securement pin. The trial is used to establish appropriatehead position, particularly in the instance where anatomically shapedelliptical (non spherical) humeral head prostheses are to be used.Markings on the trial are used to key the position of the head relativeto the humeral bone. Of course it will be clear to one of ordinary skillthat the trial heads may vary in material, color, and implements formarking and manipulation, and as such, the exemplary embodiment ismerely representative.

The disclosed stem trial broach handle has a generally elongate profilewith a proximal handle and engagement element that removably attaches toa stem trial or implant. The broach handle instrument also has a depthindicator or guide that enables precise alignment of the plane of theproximal surface of the stem relative to the plane of the bone cut. Thedepth guide also ensures that the stem is sunk within the bone at adepth that allows precise contact and engagement with the metaphysealshell. As shown in FIG. 55, the exemplary stem broach handle has a depthguide that is generally plate like and positioned at the distal end ofthe handle, to interface with the bone cut and precisely orient the cutplane with the plane of the proximal end of the stem. Of course, it willbe clear to one of ordinary skill that the broach handle instrument mayvary in material, length, shape, and implements for guiding alignmentwith the bone cut, and as such, the exemplary embodiment is merelyrepresentative. In alternate embodiments, a guide element other than aplanar disc may be positioned at the distal end to confirm alignmentwith the bone cut. Likewise, any of a variety of handle features andconfigurations known in art may be utilized to facilitate handling andpositioning of the instrument relative to the stem and humerus.

Additional Shoulder Arthroplasty Components

This disclosure also contemplates additional shoulder arthroplastycomponents that are suitable for engagement and articulation with theprostheses components of the modular arthroplasty assemblies disclosedherein. Accordingly, provided herein is an exemplary glenoid implant asdepicted in FIG. 32, suitable for implantation and engagement with ahumeral head prosthesis as described herein. In some embodiments, theglenoid implant is a new keel-type glenoid prosthesis that is improvedover those in the art to enhance anchoring of the glenoid in the spongypart of bone, particularly during the immediate post implantationperiod, when mechanical engagement of the glenoid is most vulnerable. Invarious embodiments, the glenoid implant has two opposing surfaces. Onone of its surfaces is an articulation surface adapted to cooperate witha humeral head. The opposing surface is adapted for engagement with theglenoid cavity, and includes a keel for anchoring it in the glenoidcavity of a shoulder. The keel extends from the glenoid cavity surfaceof the component and adapted to be immobilized in the glenoid cavity.The keel has two opposing faces, each of which face comprises at leastone projecting fin that runs generally parallel to the glenoid surfaceand extends over at least a part of the perimeter of the keel. Inalternate embodiments, the keel includes a plurality of fins alignedsubstantially in parallel with one another and to the surface of theglenoid and each extending over at least a part of the perimeter of thekeel.

In some embodiments, the keel has fins that extend around the entireperimeter of the keel, covering both opposing faces. In alternateembodiments, the one or plurality of fins is located on one or bothfaces of the keel. In yet other embodiments, each face of the keelcomprises a recess and the fins cover the surface of the recessed areabut do not extend onto the remainder of the keel surfaces. In thevarious embodiments, the keel fins are flexible. It is the flexibilityand arrangement of the fins on the keel faces that provide improvedfixing of the glenoid in the glenoid cavity and ensure resistance of theglenoid to pull out from the cavity. The keel can be adapted forinclusion of bone growth promoters. In its various embodiments, thefinned keel further provides a substrate to encourage boney growth overtime to further secure the glenoid prosthesis in the glenoid cavity.

In various embodiments, the glenoid implant may incorporate one or moreof the following features, in all technically permissible combinations:The body of the keel has in cross section a circular or a non-circularperipheral contour. The fin or at least one of the fins extends in aplane substantially perpendicular to a longitudinal main axis of thekeel. The keel has a semicircular shaped cross section and an eccentricposition relative to a central axis of the glenoid prosthesis. The finor at least one of the fins has a substantially semicircular peripheralcontour. The keel comprises a first series of substantially parallelfins. The fins are made of a deformable material chosen from materialssuch as polyethylene or other polymer materials. The keel may have anyof varied dimensions and shapes. In some embodiments, the cross sectionhas a non-circular peripheral contour, and for example may be generallyfrustohemispherical and frustoconical in shape with a substantiallyelliptical base, and in some embodiments may have a base which iselliptical or substantially square or rectangular. The glenoid implantmay be augmented in a manner consistent with augmentation known in theart to compensate for bone loss and other defects in the surgical site.

Additional shoulder arthroplasty components include glenospheres adaptedfor engagement with the humeral implant system when a cupped prosthesisis engaged in the metaphyseal shell to provide a reverse shoulderconfiguration.

It will be appreciated that the individual components of the implantassembly may be made using a variety of materials, including metal andplastic and combinations of these. Such materials include but are notlimited to: metals such as, for example, stainless steel, titaniumalloys, cobalt alloys, cobalt chrome, superelastic metals, such asnitinol, polymers, such as polyester and polyethylene, polyether etherketone (PEEK), carbon and carbon fiber materials. Porous coatings may beprovided for any or a portion of the components, and specifically asdescribed herein or as otherwise known in the art. The components may beprovided with HA either dispersed on all or a portion of a surface,dispersed within all or a portion of the material of manufacture, andcombinations of these.

To the extent used herein, the singular forms “a,” “an,” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. The term “proximal” to the extent used herein inconnection with any object refers to the portion of the object that isclosest to the operator of the object (or some other stated referencepoint), and to the extent used herein, the term “distal” refers to theportion of the object that is farthest from the operator of the object(or some other stated reference point). The terms “surgeon” and“operator” to the extent used herein are used interchangeably herein andeach is intended to mean and refer to any professional orparaprofessional who delivers clinical care to a medical patient,particularly in connection with the delivery of care, including but notlimited to a surgeon. Likewise, the terms “patient” and “subject” to theextent used herein are used interchangeably herein and each is intendedto mean and refer to any clinical animal subject, including a humanmedical patient, particularly in connection with the delivery of carethereto by anyone, including a surgeon or operator to the extent thoseterms are used herein.

Spatially relative terms, such as “inner,” “outer,” “beneath”, “below”,“lower”, “above”, “upper” and the like, to the extent used herein, maybe used herein for ease of description to describe one element orfeature's relationship to another element(s) or feature(s) asillustrated in the drawings. Spatially relative terms may be intended toencompass different orientations of the device in use or operation inaddition to the orientation depicted in the drawings. For example, ifthe device in the drawings is turned over, elements described as “below”or “beneath” other elements or features would then be oriented “above”the other elements or features. Thus, the example term “below” canencompass both an orientation of above and below. Thus, an item may beotherwise oriented (rotated 90 degrees or at other orientations) and thespatially relative descriptors used herein interpreted accordingly. Withrespect to any references to the extent used herein that may be maderelative to an object, or to a body or subject for example that of ahuman patient, the terms “cephalad,” “cranial” and “superior” indicate adirection toward the head, and the terms “caudad” and “inferior” and“distal” indicate a direction toward the feet. Likewise, the terms“dorsal” and “posterior” indicate a direction toward the back, and theterms “ventral” and “anterior” indicate a direction toward the front.And further, the term “lateral” indicates a direction toward a side ofthe body, the term “medial” indicates a direction toward the mid line ofthe body, and away from the side, the term “ipsalateral” indicates adirection toward a side that is proximal to the operator or the objectbeing referenced, and the term “contralateral” indicates a directiontoward a side that is distal to the operator or the object beingreferenced. More generally, any and all terms to the extent used hereinproviding spatial references to anatomical features shall have meaningthat is customary in the art.

Unless otherwise indicated, all numbers expressing quantities,properties, and so forth as used in the specification, drawings andclaims are to be understood as being modified in all instances by theterm “about.” Accordingly, unless otherwise indicated, the numericalproperties set forth in the specification and claims are approximationsthat may vary depending on the suitable properties desired inembodiments of the disclosure. Notwithstanding that the numerical rangesand parameters setting forth the broad scope of the general inventiveconcepts are approximations, the numerical values set forth in thespecific examples are reported as precisely as possible. Any numericalvalues, however, inherently contain certain errors necessarily resultingfrom error found in their respective measurements.

While the disclosed embodiments have been described and depicted in thedrawings in the context of the human shoulder, it should be understoodby one of ordinary skill that all or various aspects of the embodimentshereof may be used in connection with other species and within anyspecies in any joint in the body.

While various inventive aspects, concepts and features of the generalinventive concepts are described and illustrated herein in the contextof various exemplary embodiments, these various aspects, concepts andfeatures may be used in many alternative embodiments, eitherindividually or in various combinations and sub-combinations thereof.Unless expressly excluded herein all such combinations andsub-combinations are intended to be within the scope of the generalinventive concepts. Still further, while various alternative embodimentsas to the various aspects, concepts and features of the inventions (suchas alternative materials, structures, configurations, methods, devicesand components, alternatives as to form, fit and function, and so on)may be described herein, such descriptions are not intended to be acomplete or exhaustive list of available alternative embodiments,whether presently known or later developed.

Those skilled in the art may readily adopt one or more of the inventiveaspects, concepts, or features into additional embodiments and useswithin the scope of the general inventive concepts, even if suchembodiments are not expressly disclosed herein. Additionally, eventhough some features, concepts and aspects of the inventions may bedescribed herein as being a preferred arrangement or method, suchdescription is not intended to suggest that such feature is required ornecessary unless expressly so stated. Still further, exemplary, orrepresentative values and ranges may be included to assist inunderstanding the present disclosure. However, such values and rangesare not to be construed in a limiting sense and are intended to becritical values or ranges only if so expressly stated.

Moreover, while various aspects, features and concepts may be expresslyidentified herein as being inventive or forming part of an invention,such identification is not intended to be exclusive, but rather theremay be inventive aspects, concepts and features that are fully describedherein without being expressly identified as such or as part of aspecific invention. Descriptions of exemplary methods or processes arenot limited to inclusion of all steps as being required in all cases,nor is the order that the steps are presented to be construed asrequired or necessary unless expressly so stated.

We claim:
 1. A modular system for long bone arthroplasty comprising: agenerally disc shaped coupler component that is adapted on a first sidefor attachment with a prosthesis component that is either a concave cupor a convex head, and that is adapted on a second opposite side forattachment with an anchor component that is either a plug or an elongatestem, wherein the prosthesis component defines a bone articulationsurface and the anchor component defines at least one bone insertionsurface, the coupler component comprising: a lateral edge that boundsthe first and second sides; on its first side, a recess having asubstantially planar floor and a sidewall that is defined by the lateraledge and at least one prosthesis component engagement feature; and thesecond side being substantially planar and comprising at least oneanchor engagement feature, wherein the coupler component is selectedfrom an array comprising a plurality of coupler components that includevariably positioned anchor engagement features to enable assembly of thecoupler, prosthesis and anchor components such that when the coupler andanchor components are recessed into bone the assembly achieves alignmentof the bone articulation surface of the prosthesis component with thebone that is anatomically similar to a native long bone, wherein each ofat least two of the plurality of coupler components comprises at leastone anchor engagement feature that is off-center from a center point ofthe second side of the coupler component, and wherein the off-centerengagement feature on each of the at least two coupler components is ata different distance relative to the center point.
 2. The modular systemfor long bone arthroplasty according to claim 1, further comprising: aprosthesis component comprising on a first side a bone articulationsurface that is either convex or concave and has a generally ellipticalcross sectional shape, and comprising on an opposite second side anengagement feature for engagement with the coupler component; and ananchor component comprising a proximal portion for contacting at least aportion of the coupler component and a distal portion for positioningwithin a bone, the proximal portion comprising on its surface a couplercomponent engagement feature.
 3. The modular system for long bonearthroplasty according to claim 2, wherein the shape of the couplercomponent is selected from cylindrical, frustoconical, andfrustohemispherical.
 4. The modular system for long bone arthroplastyaccording to claim 3, wherein the coupler component is frustoconical,and wherein the at least one prosthesis component engagement feature isa tapered sidewall, and wherein the at least one anchor engagement is amale taper, and wherein the coupler component further comprises: atleast a second prosthesis component engagement feature that comprises atleast one circumferential tooth on the tapered sidewall; and a surfacetreatment on the lateral edge to encourage bony ingrowth.
 5. The modularsystem for long bone arthroplasty according to claim 4, wherein theanchor component is a stem selected from an array comprising a pluralityof stems that vary in at least one feature selected from overall length,proximal portion length, distal portion length, proximal portion girth,distal portion girth, and combinations of these, and wherein the couplercomponent engagement feature on the planar proximal surface comprises afemale taper for receiving a complementary male taper on the couplercomponent, and wherein at least a portion of the proximal portion ofeach stem comprises surface treatment to encourage bony ingrowth.
 6. Themodular system for long bone arthroplasty according to claim 5, furthercomprising at least a second anchor engagement feature on the couplercomponent that comprises a bore through the male taper for receiving afastener adapted to engage with the anchor, wherein the female taper ofthe anchor component includes interior sidewalls and a base thatcomprises a bore adapted for concentric alignment with the bore in thecoupler component, the bores adapted with fixation features forreceiving a through fastener for releasable fixation of the coupler andanchor components, the system further comprising a fastener adapted forengagement within the bores of each of the coupler and anchor componentsand comprising a tool engagement feature for actuating fixation andrelease of the fastener.
 7. The modular system for long bonearthroplasty according to claim 5, wherein the prosthesis component isselected from one of a first array comprising a plurality of convexheads that have an elliptical cross section, and a second arraycomprising a plurality of concave cups having an elliptical crosssectional shape that is circular.
 8. The modular system for long bonearthroplasty according to claim 7, wherein the prosthesis component isselected from an array comprising a plurality of convex heads, andwherein the heads vary in at least one feature selected from height,shape and circumferential dimension, and wherein each head in the arrayhas a spherical apex on its articulation surface and an elliptical crosssection, and the array includes heads that have a circular crosssectional shape being defined by a single radial axis of symmetry andheads having varying elliptical cross sectional shapes being defined bytwo perpendicular axes of symmetry, and wherein the engagement featuresof the prosthesis and coupler components are concentrically aligned andare rotationally free to allow for variable rotational positioning ofthe elliptical heads.
 9. A tool for assembling a modular system for longbone arthroplasty comprising: an anchor component, a coupler component,and an elongate coupling member that aligns and engages the anchorcomponent and the coupler component to provide an arthroplasty assembly,and an optional prosthesis component wherein, when the anchor andcoupler components are recessed into bone and are engaged into alignmentby engagement of the elongate coupling member therewith, the assemblycan be fixed into a configuration that is anatomically similar to anative long bone when combined with an optional prosthesis componentwherein the position of the anchor component relative to the couplercomponent can be varied in two dimensions on a plane that isperpendicular to a central axis of the coupler component by rotationaladjustment of the position of the coupler component relative to theanchor component as recessed in the bone, and wherein engagement of theelongate coupling member can be locked to fix the position the couplercomponent comprising markings on a peripheral rim and adjacent to acentral insertion through hole that receives the elongate couplingmember to provide measurable indicators of the relative offset positionsof the coupler and anchor components.
 10. A modular system for long bonearthroplasty comprising: a generally disc shaped coupler component thatis adapted on a first side for attachment with a prosthesis componentthat is either a concave cup or a convex head, and that comprises on asecond opposite side a plug, wherein the prosthesis component defines abone articulation surface and the anchor component defines at least onebone insertion surface, the coupler component comprising: a lateral edgethat bounds the first and second sides; on its first side, a recesshaving a substantially planar floor and a sidewall that is defined bythe lateral edge and at least one prosthesis component engagementfeature; on its second side, a plug that is unitary with and centered onthe second side, having sidewalls that extend distally from the secondside and are adapted for engagement with bone; at least one through holein the form of a slot or a slit that passes from the planar floor of thefirst side through the second side and is proximate to at least aportion of the sidewall of the plug; a prosthesis component comprisingon a first side a bone articulation surface that is either convex orconcave and has a generally elliptical cross sectional shape, andcomprising on an opposite second side an engagement feature forengagement with the coupler component; wherein, when the prostheses andcoupler components are assembled, and the coupler component and plug arerecessed into bone the assembly achieves alignment of the bonearticulation surface of the prosthesis component with the bone that isanatomically similar to a native long bone.
 11. A method for implantinga modular system for long bone arthroplasty comprising: selecting froman array of components an anchor component that defines at least onebone insertion surface for insertion into at least the metaphysis of along bone, the anchor component selected from a plug and an elongatestem, the anchor having a longitudinal axis that corresponds with asuperior to inferior axis of a long bone and a transverse axis thatcorresponds with a posterior to anterior axis of a long bone; aprosthesis component that defines a bone articulation surface thatmimics either a native long bone head or a native socket, the prosthesiscomponent selected from a concave cup and a convex head, the prosthesishaving a longitudinal axis that corresponds with a superior to inferioraxis of a long bone and a transverse axis that corresponds with aposterior to anterior axis of a long bone at least provisionallyestablishing a position for the anchor component in the bone at leastprovisionally establishing a desired offset position for placement ofthe prosthesis component to achieve alignment of the bone articulationsurface of the prosthesis component with the long bone that isanatomically similar to a native long bone, wherein the position of theprosthesis component relative to the anchor component is selected fromone of the intersection of the aligned longitudinal and transverse axes,and positions that are offset from one or both the longitudinal andtransverse axis.
 12. A method for implanting a modular system for longbone arthroplasty according to claim 11, wherein the offset position ofthe prosthesis component relative to the anchor component is selectedfrom the following: zero, such that the prosthesis component and theanchor component are aligned at the intersection of their alignedlongitudinal and transverse axes; and other than zero, such that theprosthesis and anchor components do not share alignment with either oneor both their longitudinal and transverse axes.
 13. A method forimplanting a modular system for long bone arthroplasty according toclaim 12, wherein the prosthesis component and the anchor componentshare a common longitudinal axis and the transverse axis of theprosthesis component is offset from the transverse axis of the anchorcomponent either superiorly or inferiorly.
 14. A method for implanting amodular system for long bone arthroplasty according to claim 12, whereinthe prosthesis component and the anchor component share a commontransverse axis and the longitudinal axis of the prosthesis component isoffset from the longitudinal axis of the anchor component eitheranteriorly or posteriorly.
 15. A method for implanting a modular systemfor long bone arthroplasty according to claim 14, wherein the transverseaxis of the prosthesis component is offset from the transverse axis ofthe anchor component either superiorly or inferiorly, and wherein thelongitudinal axis of the prosthesis component is offset from thelongitudinal axis of the anchor component either anteriorly orposteriorly.
 16. A method for implanting a modular system for long bonearthroplasty according to claim 12, comprising the initial step ofpreparing the bone for receiving the coupler component, the preparingincluding the steps of: identifying the center point of a long bone forreceiving an arthroplasty implant, wherein the long bone has beenprepared by establishing an essentially planar bone cut approximatelyalong the line of the anatomical head of the bone having an approximateangle of inclination of 135 degrees (135°); creating a pilot hole with adrill to guide preparation of a circumferential ring to establish theperimeter of the implant using an appropriate drill bit; affixing in thering a bone head protector sleeve to prevent proximal peripheral bonefrom being crushed; reaming the bone in the center of the ring using anappropriate bit such as a Forstner-style bit; optionally collectingremoved bone for grafting; further refining the reamed bone using alarger diameter of reamer to enlarge the proximal, but not distal,aspect of the bone hole to establish a tapered bone hole for receivingthe coupler component following placement of the anchor component.
 17. Amethod for implanting a modular system for long bone arthroplastyaccording to claim 12, wherein the offset is established using an offsetmeasuring tool that measures incrementally the distance from theintersection of the longitudinal and transverse axes of the placedanchor component to the desired position for placement of theintersection of the longitudinal and transverse axes of the of theprosthesis component.
 18. A method for implanting a modular system forlong bone arthroplasty according to claim 11, wherein the prosthesiscomponent is selected from an array of elliptical heads having varyingelliptical cross sectional shapes, each having a length along thesuperior to inferior longitudinal axis that is greater than a widthalong the posterior to anterior transverse axis.
 19. A method forimplanting a modular system for long bone arthroplasty according toclaim 12, further comprising selecting a disc shaped coupler componentthat is adapted on a first side with an engagement feature forconcentric attachment with a selected prosthesis component, and that isadapted on a second opposite side with an engagement feature forattachment with a selected anchor component, wherein the anchorengagement feature is positioned on the coupler component to provide theestablished offset between the prosthesis component and the anchorcomponent.
 20. A modular system for long bone arthroplasty comprising: aprosthesis component, an anchor component and a coupler component thatare engageable to provide an arthroplasty assembly, wherein the positionof the prosthesis component can be varied rotationally around a sharedcentral engagement axis with the coupler component, and wherein theposition of the anchor component relative to the coupler component canbe varied in two dimensions on a plane that is perpendicular to thecentral engagement axis of the coupler and prosthesis components byselecting the coupler component from an array comprising a plurality ofcoupler components that include variably positioned anchor engagementfeatures, wherein each of at least two of the plurality of couplercomponents comprises at least one anchor engagement feature that isoff-center from a center point of the coupler component, and wherein theoff-center engagement feature on each of the at least two couplercomponents is at a different distance in at least one dimension that isperpendicular to the central engagement axis, and, wherein, when thecoupler and anchor components are recessed into bone the assemblyachieves alignment of the bone articulation surface of the prosthesiscomponent with the bone that is anatomically similar to a native longbone.